Yes and again, your example is an action of directly and consensually helping kids. The kids directly get the hot dog you made. They consent to eating the hotdog. They aren't forced to eat it. You aren't giving the hotdog to a third person who will then eat it and then by extension later help a child in some other way. Which btw, they should be doing in the first place.

I’m gonna be the odd one out, I guess.

At a picnic, it’s likely that you’re not grilling just for the kids; and likely that grilling means you’re excluded from other activities.

Activities like playing games with said kids.

Bringing them into the picture instantly becomes manipulative, where you can make the same argument (that they need to be cooked, and someone has to do it,) without it.

Edit to add some background: I’m an uncle, but not a father. At family picnics, my bro and parents like to use my nephew and nieces as a guilt trip so I let them task dump; even though we’re organized enough they’re fairly equitable (including watching the kids as a task, even if it’s more fun.)

SiL in particular is egregious.

It’s always manipulative, even if when the child’s wellbeing is directly involved, it’s maybe called for. But that really shouldn’t t be the case at a picnic.

Most parents don’t even realize they’re doing it- ie asking you to cover their summer vacation (and not reciprocating.) at work.