As a piper in Kentucky (where we get quite a range of temperature and humidity), I'm not at all surprised at seeing that the southern states pipe bands tend to go for lighter weight kilts. The Louisville Pipe Band wears 11/13 oz. wool kilts, and sometimes after a late spring or early fall event the liner around my waist is completely soaked through with perspiration when I get home & take my kilt off. (We generally take mid/late June and July off as it's too hot and humid out to kilt up.)

I'm also not at all suprised about Alan's experience that the athletes wear the less expensive poly/blend kilts. Were I to be participating in the heavy athletics I, too, would wear something that I'm not afraid to get dirty and/or tear that would clean up easily (washing machine) or be easily replaced.