If the kids aren't bothered by it let it go. If they are then deal with it.
However the problem is you have a larger problem. The kids are have developed the ability to lie to parents with our reguard, now before you start blaming mom, consider this. If they may just as well being lie to you because they know you hate mom and think its what you want.
my step kids would do this all the time, rarely are they only lying to ONE parent. my children tried to do it a few times but quickly discovered that their dad and I DO infact talk and we nipped that pretty quick.
So I would suggest you try to set up family counseling with the inclusion of mom to start dealing with some of these issues. at the very least you need to discuss this with her and the kids should be involved so they see that you talk.
On that note the counselor is NOT a member of the court and while he can ADVICE you, you must take his advice and go into court and request the change. Unless you have a clause in your decree that allows you to deny visition under certain grounds you can't. Adeguate is open to interpretation. Does state law require seperate beds? and if so is there an exclusion for short or temporary situations. (which this is)
If all they need are seperate sleeping bags, then send them with them. you might also want to TAKE them to moms and see for yourself.