The Australian Regulations require security operators to do a manual inspection if requested. (Does not necessarily apply elsewhere). I have an email from the Dept of Transport Safety - several in fact - that make this quite clear, quoting chapter and verse. Many/most operators and their supervisors are unaware of this or just don't want to know. I used to carry a copy of the emails and used them a few times but, frankly, up to 400 ISO the carry-on baggage scans aren't a problem.
Somebody is going to ask, I'm sure and, yes, I still had a problem with a particularly aggressive supervisor who said he didn't care what emails I had, my film was going through the scanner. I asked him to fetch the Airport Security Manager to settle the matter and to record my complaint and he huffed and puffed and then deflated. His attitude still had some way to go. But I only ever did that once.