Their lies are in their on going dialogue to their customers, a constant veil of deceit over a few years now, some (a few) of those customers have supported the banners. I have no intention of being selective in trying to unravel their lies, but it is not too hard to follow their actions, as reported by you. I have no intention of supporting the owners, as you do. Since this commenced you have waxed and waned in your thoughts of how the club have responded, but you are now an advocate of their robust cooperation, a cooperation that has taken you some real effort to gain.
I have no intention of getting involved, beyond my original contribution (there will not be another), I still question the engineer's structural concerns (it's a theoretical nonsense), I have offered you the basis of an idea as you childishly continue to request an engineers report, but all you really want is an argument. In the real world this would have been resolved the next day, if there was a will to do so. They could try talking to
these or Google some other specialist, as it is what any consulting engineer would do. The whole idea (the point I questioned) of there being a concern over structural movement, caused by the 'sail' effect of these banners is still laughable, if being used as an on going technical concern. There should be more concern over the health and safety issues of banner breakaway in high winds (if someone is daft enough to hoist them). Is the real problem a banner that is too big, perhaps?