Yep, it's generally not a problem either way. Masts that have been squared-off on the bottom obviously don't turn and usually work fine. On the other hand, there are thousands of Sunfish sailboats out there with round masts in a round hole and nothing to keep them from turning a bit on use, and they also work fine. About the only non-stayed mast where it makes much difference at all are sprit-rigs. In that case, we often encourage the mast to turn as needed when sailing and tacking as it tends to keep the tension on the snotter and sprit (and thus their ability to peak-up the sail) consistent from tack to tack. Even in this case, it's not absolutely required, but it usually performs a bit better.
