-Not having a condom is not having protection while being screwed.
Not having a model release is not having protection against getting screwed.
-They both usually have fine print on them that I don't bother reading.
-If you break a comdom while in use, you can be guaranteed 18 years of pain and suffering
If a model breaks a model release wile in use, you can be guaranteed some compensation.
-One of the two can't be rolled down over your head and blown up with your nose to impress people at parties.
-You would never plaster your newly married best friend's car with model releases
-Girls are usually more excited to participate when you don't have a model release.