Anything which in any way makes it harder for buyers to pay should be avoided.
The only block I've ever used is the 2 non-payment strikes and I even question that one when I see buyers with hundreds or thousands of feedback blocked because of it.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.