Sorry about my previous post, you must've just posted while I was typing it.
Even idiots "shouldn't" be able to install it backwards: the little tab on the bulb's housing will still be there - and that enables the 4R harness plug to latch onto the bulb. So, as long as you latch it and here the "click", you'll be fine. Or, just match up the plug with the socket the way it should go if you didn't mod it. Basically just looking at it will idiot proof it.
Yeah, dr. dremel is the easiest way. Soldering iron or utility knife will work too. My point is that the $25 is probably best spent on a cheap rotary tool or a nice soldering iron, which you can use for this mod as well as future projects, rather than just tossing down the money on the jumper harness.