I was just saying on another thread...
CBF often forgets where I am (like when I'm in another city, visiting FBF) and calls me when he's on his way home from work. I have been taking his calls when I'm there. FBF has been very understanding and doesn't seem to mind. I doubt he'd tell me much if he did though. They two are very good friends. I only had one time when FBF called me, while I was at CBF's family's house for dinner. I took the call (we weren't yet eating), because I want to be sure they both know they're important, and I won't blow of either of them for the other.
Me, as the hinge, I feel some responsibility to be sure they both know that I've not forgotten them while I'm with the other. I don't think they give a fig about it, it's mostly my thing.
What GG said, you always have the right to ask.