doubleu-anker, I don’t see how your security issue (or lack of action) relates directly to the CAA’s investigations.
If as you state the issue can affect safety, then use the appropriate reporting channels. In the UK an ASR / MOR, or file a (confidential) report via CHIRP.
If a crew member considers that a preflight experience will affect operational performance, then s/he should declare them self unfit for duty. Whilst this will probably require formal reporting and even cause personal concern about investigation, it should bring the issue to the attention of management as an issue requiring action.
If the issue is serious / widespread then the CAA or other authorities would become involved.
I understand that the CAA welcomes all safety reporting, but you will have to accept that they would be the arbiters of the seriousness of the issue.
This might be seen as an interesting reflection of many crews failure to report issues involving ‘near loss of control’ or ‘near runway overrun’ because they, the crew, decide that it isn’t a safety issue!
Perhaps this is what the authorities should be looking at.