Why do FIDE tournaments have rest days on weekends? I'm one of those sad geeks that, instead of watching football of some sort or another, prefer to watch the super GM's battle it out whenever my schedule allows. This weekend I was looking forward to following the FIDE Grand Prix Series, just to find out to my dismay that they are having a rest day on Saturday.

Now I understand that chess is a demanding game and that GM's need their rest, but why do they schedule rest days over the weekend, when spectator interest is at its highest?

Why not have rest days on Mondays and Thursdays, for example? Or alternatively, have a system where players have various rest days, but there is at least one game going on every day for the duration of the tournament.

Surely it is in the interest of the game to maximise the spectator value, which in turn improves the commercial value of the game?
I would say the problem is that the Grand Prix is a Fide organised tournament. If you see how often those tournaments are played in almost completely empty halls, it is obvious that Fide doesn't much care about spectator value.

Some other tournaments conveniently have an uneven number of players, which leads to an extra rest day for each player, "unnoticeable" to the spectator. 

Generally non-Fide tournaments try to maximise the income from visitors, which means the weekends have to be played (From the top level tournaments I visited, I would estimate that weekend days draw double to triple the number of visitors compared to workdays.).