A quick philosophical note on rules writing.
Basically, when I write rules, I write them for reasonable GMs and reasonable players.
I do my best to write rules that are airtight, and which don't have big screaming loopholes in them. I try to anticipate the ways the rule can be misread or misunderstood, and how my notoriously nit-picky players will quote them back at me.
But sometimes, you can't make airtight rules to cover all cases and all situations with a simple set of guidelines. You just can't. You just need something that worst most of the time in most of the cases, and which gets you close enough for a GM judgment on the rest.
And people can sneak in abusive characters or leverage those rules to do abusive things.
Those people? I don't write rules for them.
I write the rules with them in mind, but they aren't my target audience. If I can please them too, or stop them in their tracks, great. If not, well, it's the reasonable folks I had in mind anyway.
Rules in an RPG are written with the basic assumption that there is a GM. A referee. Someone who judges the rules. There will one at the table, and he or she is the final arbiter of the rules. Not only that, but they are generally written with the idea that the GM will be reasonable, the players will be reasonable, and that you are basically cooperating to have a good time (even if you are in conflict in the game).
For years, I've had a solution to this, which longtime readers of GURPSNet-L and other online GURPS forums might recognize. I call it the "DMG rule." That is, basically, "hit the guy who suggested that ludicrously rules-abusive idea with the spine edge of my 1st edition AD&D Dungeon Masters Guide."
As the GM, I've long felt that the goal was fun and enjoyment, and using the rules to get to that end. Abusing the rules - whether it's designing an oversized weapon and then scaling it down for smaller folks to see if you can't lever out a mechanical benefit for no cost for your average sized character, or misreading a spell so it does something game-breaking, or abusing grammar to make a rule do weird things, or otherwise attempting to de-fun the game for personal benefit - is bad. It's not enjoyable, and you'll get whacked with my DMG (usually metaphorically rather than literally). I figure that's ultimate the GM's job, and the player's job is to accept that.
So if you find a rule which, applied creatively, can break things, a good first-pass solution is to fix the desire to abuse it. It:'s another variation of my annoying question - "Has this come up with reasonable players?"