To be fair, when I was an IC it was far easier to decide the day of if I was going to attend a meeting because aside from standups and sprint planning/retro, meetings were few and far between.
Nothing against that, but that’s when tentative makes more sense. I tentatively accept many items for similar reasons, but I work to always attend stuff I accept.
One person I met had auto accept turned on and only decided to attend on the day of the meeting.
It’s fascinating to me the world of personal disorganization.