Bit of background- DP and I have DS, 2.6 and DD 15 months. My Mum lives a few hours drive away, and visits once, maybe twice a month, depending on what we're up to. She is considering moving to be closer to us next year when she retires. Mum appears to love being a GP, always says she looks forward to seeing the DCs.
Mum was always a fairly strict parent with my three siblings and I, in terms of manners, behaviour etc, which I think has stood us in good stead as we've grown up and become (fairly, ahem) responsible adults. We were smacked as children, although it hasn't (until now maybe), had any lasting affect on me. I've never looked back on my childhood and thought anything particularly bad happened, or that my parents abused us because they smacked us, and my Mum even says herself that she rarely did it beyond the age of 5, as the threat of it was enough to make us step in line pretty quickly. As a result, I always thought that when I had children, I would smack them as a last resort if they were exceptionally naughty.
However...
Since having DS and DD, I have smacked DS on the hand or on the bottom if he has pushed my buttons, BUT I have felt ridiculously guilty, and it just hasn't sat well with me and I know that i've done it when i've lost control, which is never a great thing to do. As a result, i've started to make sure that I walk away if I feel i'm losing my temper, despite what i've always been brought up to think by my parents. I've realised that DS is still too young to understand certain things, and distraction techniques tend to work best. Not negotiating (I can't bear it when a parent spend hours reasoning with two year old Hugo, about why the can't do X), but a firm 'NO', removal, and distraction.
I'm not a push over, in fact DP and I are shit-hot with manners (DS says please and thank you really well already) and behaviour, especially out and about, but otherwise I think our DCs are still so tiny, and we have lots of fun with them whilst instilling said basic manners and age appropriate behaviour.
My Mum, however, thinks that these days parents are too soft with their children, and (in her words) lots of children need "a good slap" and are "brats".
She came to stay with us for the night yesterday. DP was working in the evening, and I needed to pop out in the car for half an hour to pick something up, and Mum said she was happy to look after DS and DD. I returned, put the DCs to bed, and sat down with a glass of wine. DS, who usually goes to sleep well, called me upstairs a couple of times, before finally going to sleep. I said to my Mum that he was probably excited because she was here, and Mum said "I doubt it, I gave him a slap on the legs whilst you were out, because he kept playing with the net curtains after i'd asked him not to. He ran over to the other chair wailing and holding his leg". She was laughing a bit as she said this, and my face must have looked a bit blank and shocked, because she quickly said "I'm sure it was just the shock, rather than it hurting".
I just didn't know what to think for the rest of the evening. If I don't feel comfortable smacking our DCs (DP has never smacked DS), i'm not sure I want anyone else to. I guess i'm confused because i've been bought up to think smacking was 'normal', and i'm still very much of the ilk that 'it takes a village to raise a child'. I have no problem with anyone telling off my children if they're naughty, but I'm now questioning my whole belief system. I was so sure I would smack my DCs (pre-children), so i've surprised myself with how I feel now.
I know Mum would think I was wet if I told her not to smack either of our DCs. I'm also uneasy with a few other things she's done the last couple of days, like telling 14 month old DD to "shut it", when she was making a "Ba Ba BAAAAAAA!" noise in a coffee shop today, and then told DS to "play quietly, you're giving me a headache", when he was spinning round in a circle in our living room today. I don't think he was doing anything wrong at all, he was even being very loud. 
She also is very strict about eating everything on your plate, and I find mealtimes with the kids and her stressy, whereas i'm laid back (deliberately, due to having issues i'm sure caused by how she was with my eating when I was little). The DCs are both amazing eaters, but she cringes at mess made and has told DD she's 'naughty girl' for getting food on the floor.
Reading all this, she sounds horrible , but she's mostly lovely, and i'm sure she'd be devastated if I told her all the above as I know she loves the DCs. She admits herself that she's not a natural parent. I'm just coming to realise that we have VERY different parenting styles. I'm pretty strict, but she's on a whole other level! I'm concerned about her influence on the DCs should she move closer and see them more. I not sure if i'd leave the DCs alone with her in future. My in-laws, on the other hand, are fabulous, and DS and DD adore them. DS wasn't keen to hold my Mum's hand today out and about, and didn't want to go downstairs and see her this morning. If MIL were there, he'd be all over her, and i'd be ignored- that's the contrast that i'm starting to see.
As I said previously, i'm really questioning my whole belief system now. Trouble is, DM thinks that I think the same as her still, but I don't.
WWYD? What do you think? I'm not sure what i'm asking here really. Just needed to spill. I really don't want to fall out with or upset my Mum, but I'm not sure where to go from here. I'm not scared of DM by the way, I just want to be diplomatic if possible.
Yikes, that was LONG!