Do they really need to be answered?

Actually, they do.
For example, why didn't Alex want to screw Dana in Puppetmaster (1989)?

She asked him in, and he declined, saying "I don't think that's such a good idea".

Is it because he thought that by bopping her, she'd be able to cast a spell (or enter his mind and control him)?

Otherwise, refusing her didn't make much sense. But that's just me.