My family and I run a 24 lane center and oil the lanes every day no questions asked. Typically we oil at 4pm before the leagues and 9am on the weekends and again before weekend night leagues.
Have we run the lanes with different patterns for people, sure but it's planned in advance ....if tom dick or harry comes in un-anounced and ask for oil, most likely it will not happen. Especially on the weekends where you make 90% of your open play dollars. Now if it's slow and tom calls me up a while before he comes in, I wouldn't have a problem running some lanes for him.
I think for the money it costs to run a few lanes, if it's possible you should oil them. Dpending on the factors of being busy, etc.