Dog allowed in one bed and not on another.?

I own a 2 months old shetland sheepdog. I want to allow her on my bed (not to sleep on it). I think that she'll be able to differentiate and will not get up on their bed, but they're concerned about it. Would se understand to be allowed in one bed and not on another? I'll greatly appreciate some reliable source to be able to show them. Thank you.