I saw a post on Facebook from my local luthier. He was warning guitar players from applying bug spray containing Deet and then handling guitars with a nitrocellulose finish. He said it will "melt" into the finish and he see's it every summer.
I don't think the luthier was talking about direct application to one's guitar. He was warning of applying repellent to arms, face, hands, etc and not paying attention to residues spreading to the guitar's finish.Why would you want to spray your guitar with bug repellant?