Yes, I have.
My
F2P warrior wears two ilvl 28s and has another 2 in the bank. The farm was not particularly bad. I leeched off some druids who were farming pigs at Fallhaven. It took several hours over several days (over 20 hours total) but it was mostly time spent watching netflix while i pressed my thunderstrike key every 10 seconds or so.
Problem, for F2P, is that folks arent really farming those pigs (or mobs in nazmir) for vendor trash anymore. So getting the greens on a F2P can be a bit more troublesome. If you want to farm them for a vet, its significantly easier and you can read all about it in the ilvl 28 farming compendium.
The good news is, you dont really need them. Like, I could use the cloak from Freehold with a socket proc. And I could put on some TBC dungeon shoulders. I lose a bit of vers but I gain a gang of crit and a socket slot. Fairly even trade there. I dont have socket rings and honestly I cant say I feel hyper compelled to go get them, either. Thats an "eventually" thing.
Outside of classes that just *have* to stack mastery, I think people overvalue the ilvl 28s a bit. Not that they arent good. They really are and they allow you a bit of flexibility in your gearing. But if you cant be arsed to get them, its not like there arent alternatives.