The reason for this is that bidets have had a massive upswing in popularity, and unfortunately many are poor quality and/or fit, installed incorrectly, or both. My family mostly works in the trades and I did as well in college, would not call myself a pro but I'm the friend you call when you have a plumbing problem and want an opinion before calling in a real plumber.
The number of poorly fitting bidet attachment seats that have been badly installed I've seen is quite high. If I owned the bathroom and someone wanted to add a bidet, I too would have my concerns. A ban is crazy, but I think it's totally valid to at least have a plumber inspect and sign off on the work.
Not sure what you mean by poorly fitting. I've only purchased one bidet attachment but i don't see how it could do any damage unless you don't turn the water off or empty the toilet tank on install. Are you saying the water line leaks on some bidets after install?
Not a plumber but I’ve installed a few bidets in my homes and it’s easy to see how the flexible supply line could leak if tightened too much or not enough. Toilet braided steel supply lines themselves are supposedly supposed to be replaced every 5-10 years to reduce the risk of bursting.
I put water alarms connected to my security system behind each bidet equipped toilet.
I can definitely say that my cheap first bidet leaked after about a month on instal. Not from the water lines but rather from the case of the thing became slightly unwelded.
Mine has a pipe attachment that's flimsy plastic, and tends to eject itself after a while. It'll definitely lead to flooding, so I've installed a water sensor under it.
The number of poorly fitting bidet attachment seats that have been badly installed I've seen is quite high. If I owned the bathroom and someone wanted to add a bidet, I too would have my concerns. A ban is crazy, but I think it's totally valid to at least have a plumber inspect and sign off on the work.