Comment 1 for bug 284038

I think that people that needs this safeguard wont notice if they have revisions to push (in addition to the uncommitted changes in the tree).

Since the tree check is not cheap, we don't want it to be done by default either.

I think the best solution is to add a --strict option to the push command (defaulting to false).
If not specified on the command line, we can additionally check a configuration variable so that people can opt-in either from bazaar.conf, locations.conf or branch.conf (to ease deployment since the original use case is more about a team policy than an isolated user problem).