I fly often to markets with significant leisure traffic, and when I'm in Y I'd say there's a 25% chance I get asked to switch.

I've said no to just about every request for an exit row for one simple reason- it's a very good seat, and those asking are by law adults.

I've said yes to EVERY single family request, and I'm often downgrading my seat. Usually bulkhead, occasionally E+ into E-. Yes, I travel a ton and have "earned" the right to select a better seat. I also travel enough to have a better understanding of what constitutes a good seat compared to average than most of my fellow travelers.

I have a conscience and I have my own family. I've been irropped into having to ask for seat switches and it's not fun or easy. Many of those asking with a family are either unlucky or simply ignorant to the booking process. If it's a financial consideration on their end, I'm just as compassionate for that. In short- I don't care why they're not sitting together. If I have an opportunity to switch for them, I will. I've never been placed in a middle seat, because it's rare everyone in a family has a middle. I might feel differently in that scenario on a flight over 2 hrs, but other than that there's been no reason for me to say no.

I will say that the vast majority of fellow passengers do the same. Sure, some roll their eyes and complain, but most move.