Breaking family rules while visiting relatives?

[DancingNancie81]

We will be embarking on a long road trip with a 16 mo old (good luck to us!) to visit grandparents. His grandparents only get to see him couple times a year, and i've already flexed on some rules, such as letting my mother in law drive with him in the car (she's a HORRID driver) - I agreed she could drive in their small town only, no highway/city driving. Anyway, there are now more rules (i should say preferences) that she's pushing, i.e. what he can eat, what he can play with, bedtimes, etc. She also is ignoring my advice to lightly babyproof, even though they leave the doors open (there are guns in the house! ), and glass on small tables - She is absolutely stubborn and will only hear wjhat she wants, is disregarding my wishes, and my husband is of no help since he knows it will make his dad angry if he talks back to his mom. Should i put my foot down and risk looking like a jerk/offending his parents, or let it slide for vacation time?