BillO:
I think I've entered the twilight zone.Okay, one more time.... I did not design the circuit to be turned on and left that way.
So, since every single person who looks at this is assuming that they will be forced against there better judgement to use it incorrectly, I will update the design and test it to make sure it is idiot proof.
I intended no offense, just offering up my thoughts and trying to be sure that I understand the circuit. 
When it comes to these microcontrollers, anything can happen. The output pin being left high wouldn't be an unusual situation during development, so how else should the circuit be analyzed? I'm thinking that just adding a blocking cap on the base along with a pulldown and it should be well protected from DC. At 50% duty cycle, everything should be fine, but you might want to use a smaller resistor on the base since hfe at large currents is as low as 20, unless I got it all wrong.