Rubber bands allow the wing to shift/move/pop off in the event of an "unschedualed" landing.

The down side to rubber bands are: the inconvenience, the bands "cutting" into the wing and if you don't put an adequate number of bands on the wing WILL SHIFT DURING FLIGHT, especially in high G manuvers, and, IMHO, it looks "tacky".

Bolting the wing down eliminates many of these problems, HOWEVER, in the event of an "unschedualed" landing, not only is the wing subject to more damage, but the fuselage as well.

Considering that the majority of people learning to fly with an instructor these days use a buddy box, I would build the plane as called for in the plans. The chances of an unschedualed landing are very remote, while the wing shifting during flight is still a good possibility.