That is because of the quality of some jewlery over others. Most high grade surgical stainless steel is non-ferrous, which is why people with hip implants and other surgical hardware from fractures or other implants do not set off the metal detectors. As more people entered the "lets make and sell piercing jewlery" craze the quality of the material went down. Always insist on high grade surgical stainless and you can't go wrong.

(nods head) . . . and also for healibility, durability, and health reasons.

Although people in the pierced community still cannot agree and will argue passionately about whether or not this jewelry will still set off alarms.

There are many newer places that are using technology that is both ferrous and non-ferrous now. When all they worried about was guns and knifes it was generally only ferrous detectors I believe. I think they need to go to the xray style.

My dad flies out of town and back almost every single week. Surely you're not suggesting it would be medically reasonable for him to get X-rayed 100 times a year?

Backscatter X-rays.

Surely x-ray would be a choice for people who set off the detectors?
Let's face it - if you knew x-ray was an option (ie you have piercings you can't remove), you would go for an alternative?