Gallbladder polyps can be cancerous, but rarely are. The size of a polyp can sometimes predict whether it's cancerous or noncancerous. Those that are smaller than 1 centimeter are usually noncancerous and require no treatment. But your doctor may suggest follow-up examinations to look for changes in gallbladder polyps - they can, in some cases, grow.
If your polyps aren't blocking the outlet from the gallbladder, or aren't causing you pain/discomfort in other ways, probably nothing would happen if you didn't remove the GB. However, the GB would have to be monitored from time to time to make sure the polyps weren't growing. According to reports, polyps larger than 1 centimeter are more likely to require removable of the GB.