Here's the scoop: I got a gig coming up that I'd like to turn my bass into a playable "Bass Hero" controller. Stupid, yes, but unfortunately (or fortunately depending) the crowd would dig it. My idea was to make the coloured buttons out of pieces of electrical tape which conveniently match the colours of the guitar hero controller buttons. No, I won't be using one of my better basses, and no, it won't be permanent. How much damage do I risk doing to my fingerboard if this a temporary mod - one gig only. Will the friction/constant pressure of playing "grind" the adhesive into the grain of the wood?
Question: Answer: Yes. The adhesive on any type of tape that would be strong enough to stick to the fretboard would certainly be messy. And electrical tape would probably not be sticky enough. I would recommend NOT putting any type of adhesive on the fretboard, unless this is a " throw away" bass, or at least you plan to replace the neck and strings, and any thing else you drag the glue on to.
My advice would be to use Blue masking tape between the frets, and wrap it all the way around the neck. The Blue masking tape is designed to have low adhesion, it's used for masking off areas to paint, and then to be safely removed. Once the tape is on, just color it with permanent markers.