Respectfully, there doesn't seem to be any "if" about it. As such, everybody already knows it's coming, so there shouldn't even be an issue of militant or non-customer service. Of course, it isn't unreasonable to expect courtesy, and courtesy works both ways. Any policy put in place shouldn't have to be arbitrarily challenged by every person who takes the attitude "oh, it's only one small bag", or the rules don't or shouldn't apply to them. And those who do challenge will no doubt get the enforcement (probably surly) that they rightly deserve.

If one wants go up against the rules, then one should be willing to accept the fact that they may come up short.