Its illegal to bring any form of "controlled container" into a football ground, seeing as it may have alcohol in it. Its necessary because theres been instances of people putting alcohol in bottles using syringes, or putting false bottoms on bottles just to sneak it into the football.
I don't understand how the club following the law can cause tension? Its actually an arrestable offence to have a bottle at a football game, would you rather that this happened? Its been the norm not to have these things at the football since the Taylor Report was published, close to 20 years ago now, why does it still cause friction?