Once a group starts proxing as a general rule, where does it end? If you're going to proxy upgrade cards why not ships as well? I've seen other tabletop Miniature games devolve to this level before.
I've already stated that -you- and -yours- can do as y'all see fit. But I'm posting this in case any of the players in my little corner of the X-Wing world read this thread. We have players who often visit this forum.
Your slippery slope argument, just like all slippery slope arguments, is not even worth considering. The reality of the situation relating to proxies is that players will do it to whatever extent is 1) practical, 2) accepted by the individuals that they play with, 3) keeps them from feeling like they are wasting money, and 4) does not damage their own experience. IF the game devolves into something around the level of soda can drop pods and cereal box landraiders, then that means that the game is weak and not properly designed to make players feel like continuing purchases are worthwhile. So, the game would be on its way out anyway.
Edited by Rapture