There are checks carried out by the staff and the ones catched are given the proper "treatment"
today there were 4-5 players from the ELO top 35 reduced to 1000 and with the possibility of a future ban.
for now the ELO top is clean and the reason you see the same players is because they are the most experienced.
as for the daily tournaments, any obvious cheat and abuse of organized play is seen by staff and dealt with accordingly.
Im not satisfied with that you should improve have like a 10 minute sigfn up period then randomly assign fights or oyu could make the tourneys like round robin where you lose and your eliminated or lose three or somthing