The only way to not have to put up with vacation abuse is to not play time-out protection members. If they have an upgrade membership simply abort the game. Basic membership users have limited vacation time and will eventually be forced to play.
Proposed measures against abusive vacation

Each player should be required to upload a verifiable receipt stamped with the address of their supposed "vacation" destination within 24 hours of their return. If it is only a purchase from a liquor store in their own city, then it's all the proof needed for abuse of the spirit of fair play (and possible reckless endangerment if they were driving that evening).

or just make it possible to make "no vacation" game seeks. I think most people would set that as their default - except maybe for people who have like 50-100 games on the go constantly.. but then again, they wouldn't be bothered at all by someone setting vacation mode during their game..
Very true.