I flew my M20C from Ft. Lauderdale, FL to Punta Gorda, FL on one tank. I was having them re-sealed and they found some damage inside one of the tanks. Since they had already removed some of the old sealant I could not put any fuel in that side. After they re-sealed the other side I flew it to an MSC to have the repair work done. Really no issues with flying as far as keeping the wings level, but it was as bit of a concern knowing that if I did have an issue with fuel or flow from the one tank I did not have the other side to use.