We thought about this years ago, it requires removing the option to switch teams as otherwise people would just switch back to CT (for instance) at the end of the half and removing the option to switch teams at all has its own problems.
Actually, despite the problems with removing the ability to switch teams, I would actually prefer it that way. Especially for custom map night so we get to play both sides of a custom map that we might never have the chance to again. We would need to improve auto team balancing and it might need more admin help (you know, like when Shaft is hacking)
But then the silenced variants of the weapons are terrible (IMO) and the novelty will soon wear off