We have had posts about this several times throughout the years---seems as if some bunnies are not opposed to eating rubberbands! Anyway, though one member did get concerned because her bunny at three rubberbands and there was a gi slowdown which ended up okay, for the rest of the members who have had this happen, they watched and so far, turned out okay. If you see a slow-down or any issue, then I would call a vet.
As far as if a rubberband could do damage to a bunny's intestines, I don't know for sure, but I would figure it would most likely pass, however, I don't know this for sure, and if were me, I would call my rabbit-savvy vet to ask.
Edited to add: Here's Dana Krempels answer to someone else who asked about a rubber band being digested. What is it with bunnies and rubberbands?!
http://en.allexperts.com/q/Rabbits-...r-band.htm