Well if you want to abuse the refer a friend program, you might as well do it right.

The refer a friend reward is triggered once an account goes omega, no matter what the source of the omega time is. This allows setting up chain reactions of referrals, you create account 1, which uses a referral of your main, then account2 which uses a referral of account1, next account3 which uses a referral of account2 and so on. This allows you to create an infinite chain of alpha accounts which can all be turned into omegas with a single plex.

To add insult to injury all of those will keep training after the plex runs out, pretty much just printing isk.

I've abused neither the referral chain reaction nor the never running out omega, because I dont want to get banned, but I'm sure other people are. The Refer A Friend TOS say something along the lines of that using the program for anything but getting new players started will probably get you banned, though it doesnt seem like CCP is enforcing that.