No problemo!

Just to add that this solution is still working fine, I haven't had to add any more WD-40 for almost a year now. I do try to keep that general area as clean as possible, so I think that helps too.

The boot release button/switch on our 2010 500c stopped working a while ago but our problem was the wiring loom between the body and the boot lid. Here's a description of the successful repair I did this morning:
https://www.fiatforum.com/500/429049-diy-fix-boot-trunk-lid-wiring-loom-500c-pictures.html
Hope it helps anybody with a similar issue who finds this thread through Google.