Is this cheating?

[PricopGeorgeCătălin]

This isn't technically a cheat. It is exploitation of a hole in the system.

Solution is easy. Just limit the association mode to managers of level 5 or above, and teams of level 5 or above.

I don't think this is a solution, is not so hard to get an account level 5 or above, you can find dozens of them, trust me there are many people who would find it and many crazy enough to open 20,30 accounts every season and after few seasons they will have a good rotation to provide them plenty of boosters to start exploiting again.