I would go. I think of these things as just temporary setbacks. I personally vacationed over spring break and ate out basically every day and all said I gained some weight. I didn't go all out, I still made wise food choices but it can be hard to keep with the program during times like this.

It took some time to undo the gains from that 4-day trip but I would not have changed a thing.

So he went. End of the story.

Since this is now a general discussion about these situations, I prefer to go out if I possibly can. I'm fairly isolated due to being severely disabled, so socialising is really important for me. As I see it, if I can't go out and eat with other people without eating too much, then I need to work on that problem rather than avoid it. I am reading up on Intuitive Eating, thinking through various issues, and finding it easier to eat a smaller amount when I'm out. (For some reason, I tend to get starving hungry when I'm out. I think some of it is exhaustion hunger. Making sure I don't eat later than usual helps a bit.) I'm probably still a few hundred calories over my usual allowance, but hey, an extra few hundred calories every few weeks won't affect my weight.

This is totally a personal thing, though, of course.