Following a post about a garbage question that was migrated to Programmers, Jeff posted this answer about some basic migration protection that is in place (at least one matching tag). That is a really good start.
Michael Petrotta then pointed out that only three of the users involved may have actually voted to migrate.
So, I have a suggestion for another way to protect from bad migrations - don't use the same simple majority rule (>3) for choosing the final close reason if it is migration.
Migration is the only close reason that actually impacts another site as well. For this reason I don't think it makes sense to migrate questions that have up to two users disagreeing. Could we require migrations to reach 5 actual migration close votes?
Possibly related question that you might like more or less than this one:
Should off-topic migration close votes be differentiated from others?