Dionisio,
What problems can arise? Plenty. Goodness, you name it: firefighter roles not well defined, logs not being reviewed timely, too many firefighters to controllers, "rubber stamping" the logs, are some that come to mind.
But the good thing about using EAM is that you do have the logs to document what was done with the elevated access, and the logs are way better in 10x releases than in the earlier releases.
Good luck!
Gretchen