Quote Originally Posted by Pelion
Against aware opponents you are probably asking to be raised with those blocking bets.
It's my observation that into the 100NL level very few players are capable of this. Particularly in the PokerStars game where under-bets are routine.

The biggest case for these sorts of bets is when you're on the river and worse hands call but won't bet. Particularly when your response to a raise isn't a close decision.