Basically, yes. It's very easy to end up herded through unless you're paying attention. Now I watch carefully and see which lines are going through the big scanner and which are going through the smaller metal detector. Most of the time, I can just get in the metal detector line, no muss no fuss.

However, when it is unavoidable (happens at smaller airports when there are fewer lines in my experience), I just stop in front of it and say in my most polite sweet little thing voice "no thank you" or "I don't want to go through the radiation scanner" when I'm told go through it. I've had people try and tell me it's safe and (gently?) badger me into doing it (at which point sometimes I try and offer a reason, but mostly I just say "I don't care"), but every time I've been on my toes enough to refuse, I've gotten the patdown instead. The TSA folks have sometimes gotten kinda freaked out/uptight or antsy, but it generally blows over pretty quickly and 80% of the time doesn't take much longer than the regular screening. The rest of the time, it takes them 15 minutes to find another lady agent to do the patdown, so I always start through security a little sooner if I can't see separate lines for a metal detector-only screening.

I also refuse to go to the 'private' screening area. If they're going to grope me, I'd rather it be in public in full view of everyone else.