Here is a suggestion that would be easy for chess.com to implement.  On a player's "show all stats" page, how about showing how much vacation time a player has left?  If feasible, it'd also be nice to show how much vacation time a player has used in the prior year, and also how many times a player has gone on "vacation".

I have one opponent who has gone on "vacation" 15 times -- and we're only up to move 30.  Fortunately he has only 4 vacation days left.  But it'd be nice to know ahead-of-time how much vacation time he has, and also the fact that I'd be playing a "serial vacationer".

Thanks, I did that several weeks ago.