There is a pretty good way to avoid this. Lars had instructed me to do this on the stringers on the bottom and sides of the fuselage. After tightening the fabric on the side of the fuselage, before covering the top surface, I used a syringe to lay down glue into the surface where the fabric lays up against the stringer. Without pressure, I simply used a heat gun to heat the glue up and viola. My fabric is adhered and I won't be getting any small bits like sand and grasses settling in between the stringers and fabric. There is certainly an argument that bits will get caught in the valley between stringer and fabric though. Hopefully it won't be wedged in and a vacuum will still remove it all.