The last technicality where a Flames GM looked silly for not doing their homework, was Button with McAmmond.
In one of his last, if not his last acts as GM, Button re-acquired McAmmond from Colorado in early March 2003 at the trade deadline, after trading him away along with Morris a week before the 02/03 season.
The league declared McAmmond ineligible to play the rest of the year, as you couldn't re-acquire a player traded away within 4 weeks of the old waiver draft and play in that same season.
http://articles.philly.com/2003-03-1...al-manager-nhl
Button was replaced in the offseason with Daryl who took on the second role of GM.
Button was on his way out for many other reasons, and his gaffe didn't potentially cost the Flames millions of dollars of money and draft picks as this one would've, but it wasn't a good parting gift, and the timing is almost 1 decade ago to the day.