Shorts can get very cranky and righteous about each little bit of slippage. But as long as new enthusiasts keep showing up, and old ones feel lenient, it's hopeless to insist on strict accountability. Even a short-lived burst of optimism is sufficient to arrange more funding, so manana always seems within reach.
Worst case: you're shorting Amazon. The bulls were right, and you go broke.
Best case: you're shorting something like Energy Conversion Devices, which eventually did run out of money and file for Chapter 11 in 2012. Shorts had been predicting its demise since the 1970s. That is a long time to wait.