Why would anyone mistake them for decorative, and why don't we just call them what they are "Sensor Arrays".
I think of them more as iconic architecture, intended to intimidate.
Security theatre. Intimidation builds pressure that will backfire spontaneously and deadly like a caged animal.
It's not like the terrain they cover is not already so dense with sensors
Who let that happen. Who's just as busy routing around the world's Parliaments as they are getting elected to and [ab]using them from inside to make that routing perhaps easier and sooner... <crickets>.
Maybe they include bomb sniffers?
Other stuff could potentially work behind those bands... nuclear decay detection, xray perhaps if the angles were right. Unless every path they're stationed at includes instant operating guilliotine gates, popup bollards, tire rippers, any BOOM laden boxtruck will sail right through happily paying it's EZ-Pass along the way. It'd be magnitudes less expensive and simpler if they'd stop doing the things that make lots of people want to kill them. Doesn't help that vast swaths of the world remain politically and religiously incompatible with each other and "diplomacy" meant to truly resolve that is always injected with dirty superiority intent. What's new in history? Lol.