Can I prescreen a guy for bedbugs? Yes. If you know his home address or even what area he lives in, visit the Bedbug Registry (bedbugregistry.com) for a list of infested homes and neighborhoods.
Can I tell upon sight that he has bedbugs? People tend to look for the typical bite pattern (three red circles dubbed "breakfast, lunch, and dinner" after bedbugs' feeding habits), but you're better off scanning his skin for a rash. Bedbugs inject you with an anesthetic so you can't feel anything, then they probe again, to draw your blood. And red blotches on the skin are often an allergic reaction to the anesthetic. Make a point to check out his arms, face, backs of hands, and neck.
Any date ideas in bug-free zones? Avoid the theater. Bedbugs love to hide in plush furniture. And although people think they come out only in the dark, the truth is, bedbugs don't care what time it is as long as they're hungry. Opt for ice-skating, bars without padded booths, or museums.
How can I subtly inspect his apartment? Look up at the ceiling. Bedbugs often congregate in a big group where the wall and ceiling meet, waiting to drop on a prospective meal from above. And since adults are the size of apple seeds, they're visible even from the ground. Also, look at the electrical outlets and light-switch plates for a lovely black-and-brown combo (fecal matter). And finally, breathe deep. Bedbugs emit a rotten raspberry scent.
Is it rude to directly ask if he has bedbugs? Just like any other vital info (are you normal? Are you sleeping with anyone else? Do you have an STD?), knowing his bedbug status is simply your right.
If he has them, is sex off-limits? At his place, yes. But as long as his clothes have been thoroughly sanitized, it's OK to bring him home with you.