I don't think throwing the challenge flag to talk to the ref is really abuse. If they are throwing it just to stop the game to give them an extra time out, there should be a penalty. But a discussion with the ref when you really believe the rules are being misapplied, like with Taaffe in the game against Saskatchewan, is not really an abuse. The officials were standing around chatting with Ken Miller, while totally ignoring Taaffe.
In strict accordance with the rules, they could have thrown a flag on Taaffe, but with Riders having the ball first down on the one-yard line, it wouldn't have made a difference.
In the Winnipeg/B.C. game, Doug Berry threw the flag on the interception in the end zone because he believed his player was interfered with (which he was, by the way.) In strict accordance with the rules, Winnipeg should have been penalized.
In the Toronto/Edmonton game, Rich Stubler threw the flag when the officials waved off an intentional grounding call because there was an eligible receiver in the area. (Which there was: though he wasn't near where the ball landed, the ball went just a foot or so over his head, so he was in the vicinity.) Toronto should have gotten a delay of game penalty.
So okay, let's start handing out delay of game penalties when a coach throws a challenge flag for an unchallengeable call. Because Lord knows, we just can't get enough of the officials. There's nothing more exciting than watching the guys in the stripes march off those yards. Ooh, I just LOVE that. What this league needs is MORE PENALTIES being called.