Some of the responses, for both sides of the argument, are just indicative of the way people embellish and exaggerate something they don't agree so they can kick off about it and feel justified doing so.
Asking someone something isn't 'demanding' or 'entitled' and likewise saying no to something isn't being heartless or a cunt.
I would say no, not merely on principle because I'd been asked, but because I know that I'd forget. I'd want to help but the issue wouldn't be uppermost in my mind because it doesn't affect me so it's likely to be pushed to the back of my mind with my own stuff taking priority. I wouldn't take such offence that has been displayed here at being asked, but I also wouldn't expect to be ripped a new one for saying no either.
Different situation but my neighbour struggles to get her car out when someone is parked opposite her drive, there's a shop and parking can be a challenge and sometimes it's the only space, it was never a problem for the previous occupant but it is for her, I don't think she's massively entitled if it's my car that's in her way and she either asks me to move it or to guide her out, or even if it's not my car but she comes and asks.
Similarly if I'm in the shower or there's nowhere to move my car to, she doesn't kick off and behave like I owe her something. I'm parked legally, it makes her life a bit harder as it is possible with a car there, just easier if it's not.
Because I've helped her out in the past and I've not been overwhelmed by a simple ask and because she's not called me a cunt when I can't help, we have a decent relationship and she does things like bringing my bin in after it's been emptied so it doesn't get nicked when I'm at work, she's taken in parcels for me and even brought my washing in and put a note through the door one day when it rained. I didn't ask those things, she did them to make my life easier.
Likewise if I have to park there when I get home, but I'll move it later on when the shop shuts and parking frees up, and watered her pots when she was away (turned out in hospital) during the heatwave and they were flagging.
It's just cooperation really, something the world seems to be losing in favour of self interest.
Society relies on cooperative actions, but they're not always possible all of the time, sad really that the go to is to not cooperate when you can and be so offended at being asked, to the point people will expend more effort making someone else's life harder on purpose. Or be so offended at that someone can't cooperate for whatever reason they need to dish out nasty personal insults and behave like the no is a personal Vendetta.