While the runaway score rule isn't ideal, it depends on how it'd be applied, and like others commented, there's no way to specify in the rules exactly when a "runaway" situation was achieved. If it gets used on average ~once per tournament, or possibly less, not that big of a deal.
I think it's important to note: the alternative to this rule is probably every machine gets set up insanely hard to prevent long games. I'd probably rather have a tourney with slightly fairer games with this rule in place than a tourney without the rule and much harder set up games.
Like DHS mentioned, the GC being the threshold for a game would make sense (as long as it was used in qualifying), and take TD's discretion out of play, which seems like a good thing.
For a regional tournament this seems like a fine rule. For a bigger tourney that draws more top talent, seems like it'd take away from some great/memorable tourney moments. Of course, the Seattle area has enough top players to have these kinds of events, though.
At least the rule is applied the "right" way. Had a TD once ask if I'd take a loss against KCB when he was in a runaway situation on ball 2 or something. I just laughed and said I'd let him end the match if he gave neither of us a strike, or KCB the strike :). I think brakelope won't let you resolve a match with neither getting a strike, though.