K.I.
I am one of those mom's who lets her kids watch "inappropriate" movies....although, IMO they have never seen anything inappropriate, my kids haven't ever seen anything I haven't seen....everyone's standards are different and I do believe that I have the right to make my own choice about what I feel is appropriate and what isn't....thus so do you!
I would never have a problem if a parent talked to me about what they wanted/didn't want a child to watch/see while in my care.
Do not feel bad about feeling this way and just bring it up...they will probably understand...I mean really, there are a million and one things the kids can do together besides watching TV.
When my kids were 10, I let them watch Jaws! Duna-Duna-Duna-Duna