The difference between saying thank-you and sorry

I’ve been mulling something in my head for a little while now and think I may have figured it out.

The past two days in each of my Geography lectures the lecturer has thanked the class for being accommodating in allowing two of the lectures to be swapped after Easter. He mentioned he was going away with his family, so the other lecturer would start the next unit a bit early and the next class he would complete the previous unit. I personally am fine with this as I’m sure most of the class is. There is very little difference between the units, and each lecture is very complete in itself making the order rather unimportant.

The problem comes with the fact that he thanked us. During the lecture, it was the first time I had heard about this switch and yet he was thanking us as if we had given permission. I’m sure we could have revolted if we had wanted to, but really we had little say in the matter.

In my opinion it would have made more sense if he had apologised for the switch and just left it at that. Sure it puts 'the blame' on him but isn’t that where it should lie? I think it makes more sense if  he had just said he was sorry there would be a switch in the lecture order, but it would be to allow him to spend time with his family.

Anyway, tell me your thoughts? Is this just me, or maybe a Canadian thing, or do you think it really doesn’t matter?