I've got a question concerning a possible mining strategy.
I've not found any proof of the strategy, but it seems reasonable to me.
If two mined blocks inserted in the block chain include the same transaction (not a double spent, but simply a transaction mined two times), one of the two blocks is discarded (assuming that all the other transactions in the two blocks are legit).
This is a probable fact, since each transaction is shared/"broadcasted" by a user. Therefore, a possible mining strategy may let miners keep a list of transactions, mine them without letting others know such transactions exist, hence publish/spread them, just before sending the just mined block. In this way, the probability to generate a potentially invalid block is reduced.
Am I right? Is this strategy adopted or not? Is it reasonable?