The front door

[MadderHat]

So, I have a 2.5 year old DS and an 8.5 month old DD who is crawling and pulling up. DS is very responsible for his age (insisting on holding hands by roads/carparks etc), but even so he is only 2.5. DD is into everything, copying him as far as she can, chasing him and my instinct is she's going to be much more of a handful with regards having to safeguard against her.
We live on a side street, but have commuters parking and a nearby train station which DS loves, across a road which people go too fast on. There are no gates on the front garden; though DS is pretty good about not going off the drive without permission, I'm always on alert when we're outside.

Our front door is one of those plastic doors with half-height handles (no chance of a chain, and that won't help when it comes to other adults getting in or out). It is locked from the outside on just pulling/pushing closed, so that's the habit we have got into. When you push the handle up, it's then much harder to push the handle down as the hooks engage, then you can lock it with a key. (All the other exits are key locked by default.)
DS has just discovered he can open it when it's just been pulled closed. He can't when it's pushed up (yet).

So far he has only opened it twice, both times trying to be helpful to me, when we're on the way out. I've not actively discouraged him (as I was surprised) but didn't praise or thank him. He also tried and failed once when it was pushed up, and I said it was only for mummy or daddy to open.

DH reckons that we should just teach DS not to open the door, and should push it up as a default but not lock it because of the increased delay on getting out in a fire, or when answering the door to the postman etc. DH so far hasn't managed to even remember to do that as he leaves/enters the house unless I've reminded him (and he typically leaves the house while I am asleep in the morning). DH reckons the risk of DS getting out vs fire risk is small.

My mother and MIL both think we should be locking it. I am inclined to agree with them. No point shutting the stable door after the horse is bolted, and if something awful happens first time could we live with ourselves. Plus, we probably will have to for DD anyway.

What's the Mumsnet consensus on this? Lock (and teach anyway) or not lock and rely on teaching?
Once DH gets an idea into his head, it really sticks and I'm likely to be told I'm overly cautious and laughed at and ignored. He also is a good arguer, and I'm not. So what arguments would you use, if you think we should lock, bearing in mind that a simple "what if he got out" isn't a strong enough argument?

We lock our front door for exactly this reason as it's the same kind of door (live on main road with no gates). It's never occurred to me to be a huge fire risk, the key is close by the door at all times.

I think if the key lives in/near the door then it's the work of a second to unlock it in the case of fire - which after all is massively less likely than DS learning to open the door and doing it seventeen times a day. Even if you teach him not to, you can't rely on him not doing it till he's about five.

Lock the door and hang the key from a small hook at the top of the door frame.

My front door is kept locked all the time. The keys just stay in the door in the day, and are put nearby at night.

We have a similar sort of door and have a security guard on it (like a chain, but more of a hook-and-eye arrangement). DH doesn't always remember to use it, but I do, after 4 yo DD came to tell me "there's a man at the door mummy" It was only our neighbour but I hadn't heard him knock and she'd just opened the door. Could have been anybody.

I would lock it, once they are able to get out that risk is always there, what if he opens it and your dd goes out after him, at her age she would have no sense of cars or danger at all, and your ds still going to be limited sense really as he is only 2.5.
I keep the chain on mine always, because I know my 2 yr old can open it too and its just not worth the risk, even though if he went out i dont think he would be likely to go out past the front gate really, but you never know what stupid idea they may get one day that just makes them do it, so cant take the chance..

Lock - but don't do what I did, which was to leave the spare key in the lock, and then go out and pull the door shut, thinking that I could get back in with my normal key. I couldn't! Had to climb over an 8 ft wall, then jump down, to let myself in the back. Thank goodness i had the back door key on me!

We don't leave keys in the lock - he can do them, and they're more of an interesting temptation.
So lock...
any helpful hints on the stubborn husband tackling?

I am totally paranoid about fire too and hate our door for the same reason. We don't lock ours but intend to... The kids know where the key is and to go to the window/letterbox and shout fire if there is a fire.

OP, re tackling stubborn husband, would he be more willing to listen to his mother on this one? You mention your MIL thinks door should be locked.

nonickame: I could burst into peals of laughter on that one. Listen to his parents? I think he stopped that pretty early on. Though I kind of agree with him when it comes to FIL on any matter outside FIL's profession.

So far DH has said
"I just don't think he's likely to do it in a situation we don't know, and if he does, the chances of something happening are slim"
"none of the situations you've described to me are completely independent of us going to the front door anyway"

When I'm on my own with the children, I think I'm going to lock the door, that "we" is rather royal and when it's just my responsibility, well I couldn't live with myself if by my inaction DS came to harm. Plus, there are times one can't just chase after a toddler instantly (e.g. mid baby nappy change, on the loo, feeding the baby - quickly, yes, but not instantly.) That just doesn't cover the time when DS quietly goes downstairs in the morning after DH has left the house - he's got past the mummy radar twice so far, and the early morning milk delivery or the sounds of the bin lorry might be temptation to open the door. (And, no, DH doesn't think it's a good idea to shut the stair gate at night, and it clanks and could wake DS whereas without shutting it, he might sleep till 7.)