For me, my T has only ever been off for time with his family. Once, it was a drive several hours south and I was paranoid about a car accident.
But, I think I could actually go either way with knowing or not knowing. I think my knowing whether it was time off for vacation (i.e. travel somewhere) or family or a church event or whatever it was would be plenty. So, I guess I might wonder about how he is using the time off out of interest in him as a person, but not need to know exactly where he is going. But, my T tends to volunteer that information anyway. For example, there have been times that he had his son's birthday party, so he would be staying in the city that his second office is in (he commutes to my area and across the bay M-Th and only goes home Friday night through Monday morning). It was relevant in that it changed when we could do a phone call we had scheduled and he would not be able to do it from his home office and wanted to make sure that was OK with me, but perhaps I didn't need to know exactly what he had going on. Truthfully, for some reason, it doesn't bother me. His son is my little sisters' age and I am a parent figure to them, so I guess I can relate to him on that parent level without the inside kids getting too jealous.
Anyway, I think a response like "it really doesn't matter," would be hurtful to me, not because it isn't true intellectually, but because it is discounting/invalidating of the fact that it feels important to me. I would rather a T asked why I was wanting to know and try to get at the feelings behind needing that knowledge. Otherwise, if a T didn't want to say, just to make it about his or her own boundaries. The fact that she told you later probably means that she is OK with it mattering to you and she wasn't intentionally invalidating that. It was most likely just careless wording. If my T said something like that, he would probably mean that no matter where he goes, we don't "lose" the connection, like I seem to think. He has told me that he still feels connected to me between sessions or on the rare occasion that he goes away and that it is positive and good. He said even if I moved to China and we didn't communicate very often, the connection would still always be there. So, if he made a statement about it not mattering, despite feeling incredibly shut down, intellectually, I would know that is how he probably meant it. But...the feelings it stirred up would definitely be something for us to discuss and he would explain it explicitly, even if I kept saying, "I know, but it doesn't feel that way!" the whole time, just so I would know that his sense of the attachment was still positive and sustained. I don't know if I made sense there.