Define the term "Sandbagger"- "A player who plays in a category below his/her level in order to beat the easier competition."
From The PDGA -
Pros Playing Am” : Pros rated <970 may now compete in Amateur divisions offered at PDGA Tour A B and C tier events, for which they qualify based on player rating, age, and gender:
Pro Men and Women <970 can play Advanced <935 can play Intermediate <900 can play Recreational <935 can also play Advanced Master if they are of Masters age <850 can play Novice <900 can also play Adv. Grandmaster if they are of Grandmasters age
Pro Women only <850 can play Advanced Women <800 can play Intermediate Women <750 can play Recreational Women These players are awarded Amateur points for their performance but these points are not eligible for year end awards or Worlds invitations.
http://www.pdga.com/files/documents/09TourStandardsV1-2.pdf