Exactly.If you live in any of the big cities, this happens more often that you can imagine. A man goes into a bar, perhaps with friends, has a few drinks, maybe looking for a little action, becomes engaged in a stimulating conversation with a "beautiful" woman, has a few more drinks with her, and before he knows it, she's blowing him in his car and he goes for third base and POW!! the woman has a penis.
I think that in general, a good rule of thumb is that you should get to know someone before they are gagging on your ejaculate.
I see this as "buyer beware".
Honestly, if you are drunk and getting blown in a parking lot by someone you just met, the presence or lack of a penis should be your last concern.
You should be much more worried about things like Chlamydia and HIV.
Additionally, if the girl you hookup with has a penis, you don't have to worry about getting her knocked up.