Wow, 2 posts that I know something about.
You can be sure that BA security will be taking a close interest in any interference with aircraft safety systems using relevant security devices.
And I'm not going to discuss them here!
Finger prints. If crew or have fiddled then fingerprints won't help. 1. Because they have to handle these items anyway as part of the job. 2. There is only one surface on the assembly suitable to take a print from, and 1. applies anyway.