Won't hurt anything. Quite common on maple necks for it to be sealed and it's something I've done on my last few builds. Saves taping, protects the board. I guess with a lot of playing there is potential to wear through.. but I guess by that stage its genuine relic'ing.
On a side note I'm on a few Hagstrom pages and there is at least one guy who goes right off the deep end regarding the use of lemon oil as its 'too acidic' in his opinion and encourages cracking. He recommends parrafin Oil, which is amusing as a lot of 'Lemon Oil's' sold for guitars are mostly paraffin with a small amount of lemon oil or even none, just the smell added... anyway not really relevant, just saw him pop up again this morning carrying on about it. The last time I kept asking for some empirical data and all he had was anecdotes and the phrase 'go and talk to a luthier'... OK buddy.