I used this on the double XP weekend to level my Elec/Shield Scrapper to 1-50 in about 2 hours and they didn't ban me for it. It was probably just the people who made the missions.
They did some database mining to determine who got the ban. I had a few SG mates who got the boot for about a week.
I'm starting to remember this a bit better. There were several of these farms that cropped up over a week or two. The devs closed some down only to see others create clones of them.
I think you were right about when it took place though. I forgot the dbl exp weekend. The farm may have been up less than I thought.
Honestly it might have been altitus that saved me. I did as much PLing as they did that weekend (maybe not quite), but spread over like 8 or 9 different chars.
But man it was a blast to see a new character have three or four sets of level buffs on him at the same time.