When I receive for example milk chocolate as a firm gift I'll give it forward (instead of pressing it into sender's arse). I try to keep my head healthy by avoiding worrying too much things that I can't affect much. If waiter says several times that food is vegan and after eating you hear it wasn't, what to do? Probably no visit in that place anymore, but generally I haven't stopped eating out.
Things got more complicated with child. What's the line between obsession and child's own autonomy from parent's point of view? When she goes to neighbour boy's birthday party should I expect that 5-year old kid could find out every ingredients of servings? Or deny going there? How about when grandma sends wool-socks? We let her go to parties, she can keep socks but we wouldn't buy anything non vegan things to her / our home. That's the line right now, balancing between obsession-realism-idealism
My opinion is that it's better to explain why we parents are vegans and let her think things by herself than force and isolate her from everything.