The open enrollment period, when seniors can change Medicare plans, has turned into a time for professional thieves to prey on elders. It's time limited. Seniors who are dissatisfied with what they have can get a different plan, and it generally gets seniors' attention. They can make Medicare changes only once a year, during open enrollment. The rules for doing anything different with Medicare are quite complicated. The choices of plans can boggle the mind of even the most sophisticated person. Given that, seniors may be tempted to let someone else figure it out, or purport to do so.