It's different in every aiport, with every airline and basically with just about any person, esp. TSA.
You really just can't guestimate what you can expect if there is a delay or cancelation.
Bring a few extra quart size bags with you (in case one breaks or you have a kid that can fill and stash in their bag). The airports don't seem to be supplying them any longer, or not that I've seen.
As for voulchers, hotel rooms and any other type of freebie, it's a toss up. I've seen several times where an airline has passed out loads of snacks and drinks for a relatively short delayed flight and I've seen where you get nada if you are stranded in a city due to weather or any other reason for cancellation. I agree that it doesn't hurt to ask however, the airline can't do much about the weather!
I've never had my nail clippers and tweezers taken from me and I think both those are no-no's... but it just depends on the airport I guess and what side of the bed he/she woke up on.
Just be as prepared as you can!
Happy travels, y'all!