I just scoured a few of the convertible notes from 2014 and the most recent one. Nowhere is shorting expressly prohibited. It is not mentioned at all, as Renee pointed out.
I did find some interesting tidbits:
The Notes agreements that I read all contained language prohibiting Noteholders from effecting conversions that would lead to a noteholder owning more than 4.99% of ECIG shares, or 9.99% without giving notice to ECIG. The Note holder would 'promise' that they don't own more than 4.99%.
So...the Maximum any noteholder could own pre A/S increase is 30,000,000 shares IF they notify the company.
Most likely they are converting and covering as fast as they can rather than holding on to the shares.
Millstone