Debating with husband how to handle our rules for 5YO with other parents; I think he's too draconian and that could alienate our girl socially

Soooooo part of why this is a throwaway is because we're the parents other parents kind of...hate. We didn't allow any sugar or screen time before age 2. Our kid has never had a sip of soda or a bite of fast food. Her favorite foods are spinach, salmon, and avocado. Pears are her favorite "treat." She uses technology exceedingly sparingly (<30 minutes a day), and only educational material. Etc., etc., etc. Basically, you can call us The Sanctimommies, party of 3.Typically, this hasn't been an issue with other parents. We do play dates and send our own snacks, etc. It's fine. But recently, our daughter was invited to go to a local-ish theme park (1 hour drive away) with her best friend and her mother, for a full day. Best friend's household is a lot more lax than ours, and part of the outing will involve a trip to McDonald's and likely one or two soda pops at the park. Plus they watch movies and shows on their tablet in the car for longer rides.My husband wants to tell the parents that our daughter is not allowed to have McDonald's or soda, and to request no screen time in the car. I think the first could make us look too high maintenance and frustrate both the parents and our daughter, and the second is completely unacceptable. He says if we send our own food and some games for the kids to play, it shouldn't be an issue.But I worry that if we don't allow occasional one-offs, our daughter will never learn to code-switch and will be seen as too much trouble for other parents...which could affect her socialization. Plus, overall, I worry about her looking like a snob or "weird" to her peer group. We've built a foundation of healthy habits and now is the time to let go a little bit based on context. Husband thinks now is the most crucial time to solidify, and that if other parents aren't willing to be flexible themselves, then daughter probably shouldn't go with them anyway.I think he's being ridiculous and this attitude is unhealthy, but I wanted to see what others think.And also, overall, if you tend to be a more restrictive parent regarding food/sugar/screen time, how do you manage with other parents who are less so? Are there compromises you strike, or are you big proponents of "my house, my rules - their house, their rules"? via /r/Parenting https://www.reddit.com/r/Parenting/comments/7u1if2/debating_with_husband_how_to_handle_our_rules_for/?utm_source=ifttt