Wow, Traps. I guess that they hadn't read Dr Morton Shulman's bestselling book, Anyone Can Make a Million, which was published in 1966, in which he explained the concept of "free riding" and exactly how to do this perfectly legal action: sell before settlement is due.

Funny, because you were functioning under THEIR rules - otherwise the trades could'nt have gone through in the first place, right? You even went one step further: selling on the same day, versus just selling at some point before the settlement date expired (which was 5 days at the time of the book, later only 3 days). I don't know whether that was a relevant factor in order to "stay under their radar" back then?

Anyway, i'm glad for you that you were able to achieve your purposes then - congrats!