Health inspectors are forbidding this cooking technique in NYC, at least for now.
Link to NY Times Article. (Might require free registration).

I read that article earlier this week. Have there been any health issues attributed to this tecnique?

Apparently there is a risk of growing botulinum spores in the food if it is prepared under improper conditions.

I don't think that New York is out of line banning this cooking technique. Perhaps the very top end restaurants have the training, skill and facilities to properly prepare the food; but most do not.

Given my food poisoning incident last year, I would rather not take any chances of that happening again.