1 million? I highly doubt they'd go through the trouble of doing that.
Let's play some statistics.
Let's say it takes 2 minutes to look at a player's log, determine that they're playing the game unfairly, and go through the process of banning them...
1 million accounts x 2 minutes each = 2 million minutes
2 million minutes = 33,333 man hours
33,333 man hours = 1,388 man days
if they play their employee's minimum wage ($8.50/hour):
33,333 hours @ $8.50/hour = $283,330.50
So they shell out $283k to their employee's, and let's say 1/10th of the accounts banned are recurring members?
10% x 1,000,000 = 100,000 P2P Accounts being banned
100,000 P2P accounts banned @ $5.95/Month = $595,000
Putting them -$878,000 for the first month alone, and then an extra $595,000 a month due to lost memberships. Trust me, Jagex hates botters/gold farmers with a passion, but I'm absolutely certain they'd rather pocket $878k then ban all those accounts.