More of a poll than an AIBU as I don't have strong feelings either way.
We just visited DBIL, DSIL and their two DC. They live a 5hr flight away and we see them once a year normally, around Christmas time, at PILs' house. We wanted to visit their area, and stayed with them for two nights (travelled around and stayed elsewhere for 5 more nights).
While we were there the DC went to their gymnastics classes (1.5hrs each day, both at the same time). DH and DD went with them one time (the DC were very excited to take someone new), and we all went and did other stuff together during the class the second time. All good.
Then, DBIL and DSIL each individually went to gym/yoga/pilates/boxing classes themselves, each of the two days we were there. They were each absent for 2-2.5 hours each time, while the other one and their DC were with us.
I don't see a problem with this but DH (it's his DB and SIL) is a bit miffed that we went all that way "to see them" (I don't think that entirely true, we went to their area and couldn't very well not see them) and they took themselves off for half a morning/afternoon each day.
What would you think is normal? I don't exercise at all so can't really say what's reasonable 😂