jadarite: maybe this revert time is not a bad idea (at least in turn based play with long thinking times). Within 3 minutes after submitting a move, the mover can still take it bak, and it is not yet transmitted to the opponent, to avoid a race condition.

Then there is no irreversible action that may be regretted immediately after it is done, while the delay does not force the user to wait for it. The time can be used as one pleases: either think again or go on and forget it.