First: It's not really fair to the other player if instead of playing the person they are meant to, they are playing "ringers" - who may play differently, or worse - beter then the person they are replacing.

Second: Except for ponds (and new tournaments without vacation days) - On this site it should not be a big deal. Just set some vacation days and use them - there should not be a need for someone else to play your games.

Thrid: This is the pond board, and we are quickly getting off the subject. Can we please move the conversation to another board? Thanks!