Depends on how many gigs you do a year(especially in smoky bars/warm rooms etc)
Oiling wood will not harm it, in fact it will be more beneficial, As a son in law of a retired french polisher through what he has told me, untreated woods require much more attention than finished woods. Sealed wood(varnish, polyurethane etc) protects it from the atmosphere but even these finishes need polish to make them shine.
even really hard woods like ebony will eventually shrink if not looked after and use the correct preparatons(see my reply about some bass player who used aerosol furniture polish on his rosewood board...ouch!
If someone has already done this(god forbid) then it would need cleaning with a mild solution of vinegar and water, don't soak the board but wipe it with a cloth barley damp with the solution, the mild acetic acid will remove the silicons in spray polish(1 teaspoon vinegar to half pint of water)
Apply liberal amounts of lemon oil afterwards!!!
