There's no ban on pushies on the Mountain at any time. Police however strongly advise against it and may even try to deter it by talking you out of it at Ramsey. The difficulty they have is that they continue to stress that the mountain is a normal public road and subject to the same rules as all other roads, except its one way. They can't maintain this stance and at the same time ban certain users. if they did, you may find that insurance companies would insist on different cover a la Nurburgring.

Clearly anyone riding up there during TT has a death wish. As others have already said, there are too many drivers and riders going way too hard on roads they are unfamiliar with.