Chances of you experiencing a problem are very slim. I've flown through several airports in the last few months and only Las Vegas even had the scanners, not San Francisco, not La Guardia, not DFW. Both my friend and I wear thick disposable diapers and went through the scanners in Vegas with no questions asked. I don't know if the diapers were wet at the time or not, but if they are wet, that's the only way they would probably even show up at all. If they're dry, they'd be like any other clothing and that clearly doesn't show anyway. It didn't seem to me that they were even looking at the display when I went through, I think the machine is supposed to signal if it finds something worth reviewing. One time, the machine went into calibration mode, so we were simply redirected to the metal detectors without skipping a beat. Had I opted out, that would have probably led to the "enhanced pat down" but as luck had it that time, I was just ushered through the metal detector. Which only goes to show that it's all security theater anyway.
What happened to that woman's mother was bad, but there was more to the situation than the diaper. She was in a wheelchair, and something about the wheelchair set off an alert, so that led to needing more screening, and supposedly they only suggested that the diaper was in need of changing, not that it had to be removed for search purposes. I wasn't there, but after reading many articles on the incident, that was the take away.
Seriously though, don't worry about it, and it won't be an issue. If you bring it up, the person may not know the answer and might give you incorrect information or have to go find a superior to ask, or subject you to additional screening you wouldn't have otherwise been subjected to. My friend lost his wallet on the way to the airport in San Francisco, and the guy checking IDs insisted that it's impossible to fly without an ID, which isn't true. You can be subject to additional screening, but an ID is not required. That was a case where he had to wait for a superior, but got through no problem. Flying sucks these days, but go with the flow and you'll get through it.