A scheme that requires that for the thing you did over here to work, you also need to do something over there is problematic. In computer sciency terms, you've introduced a form of "coupling". (Remember the mantra "Cohesion is good, coupling is bad.")

One risk is that someone will copy/paste from your solution, pick up @questions_marks, neglect to also copy the change to $", and then wonder why what works for you doesn't work for them (and then burn up their coworkers' time (and then post to PM)).