Random works with normal rotation TDM but in Garden people cry and leave if it is enabled. Also my suggestion is better than random IMO: it will only change the teams if one team is winning more often rather than force random all the time, and it will try to balance the teams rather than randomly switch players
And you two are right that this won't stop idiots from rejoining every time they get auto'd, but I don't know if forcing people to stay in a team is a good idea or even doable