People come to Warmachine from 40k all the time and assume it is their business to cry foul on rules that they think are "broken" because that's what they are used to. This is the wrong attitude to have. When you find a rule that seems overpowered, the first thing that comes through your mind should be "in future games, how do I use this to my advantage?" That's because the people at Privateer already know about it, and have accepted it as part of the game. Which means so should you.

If you call someone out for using rules as written you are wrong. Period.
That is entirely false, and more so speaks of Warhammer2Warmachine translation teething pains than finding yourself in disbelief with a ruling. PP have admitted the Shield Wall rule doesn't work as intended. They do make mistake, and sometimes, it's more a problem to fix the mistake than to let it be. It could be this in the case of rubberbanding, because it IS a weird interaction, one which depart with the norm of unit coherency. But it isn't just clearly so.

It is however quite important that players keep questioning the rule set, so that it can improve.