Suppose opener bids one spade. Second seat doubles (takeout). Responder redoubles. Then fourth seat "bids" one club and the opener declines to let it stand.
That is an easy fix. Fourth seat has mentioned clubs, and is now forced to say "two clubs" to make the bid sufficient.
But suppose fourth seat (a newbie) says something like "double," or "double the redouble." You can't play one spade for eightfold stakes. But the bidder has presumably given away unauthorized information. So in a tournament, what would be the penalty and how would it be assessed?