I took two days off during recent school holidays and was asked by my boss to dial into a meeting on both days. The meetings were internal, in the middle of the day, and usually last an hour and a half. There was no reason why they couldn't have been rescheduled to the next day or the day before.
I said that I would not be able to dial in, as I was on leave, had planned to do something with the children, and it would not be convenient. He was v pissed off about this, and said I would not know what was going on in the office if I didn't call in. I spoke to a colleague when I came back to the office, who brought me up to speed in about 3 minutes.