I've never seen a website break because of ublock, at least not in the default config. If it's that much of a problem you can just remote in on grandmas computer and disable it for whatever website.

I think that beats remoting in when granny inevitably gets scammed by an ad.

There really is no excuse in my mind for not running an ad blocker. It's as vital to personal computing security as firewalls and anti malware.

Blocking ads helps grandma not accidentally leak private information that could have disastrous consequences, for example, getting scammed out of their money.

Not blocking ads helps grandma visit a few more websites that don't work well with adblock.