It would be a fantastic form factor. After all, such a device wants a decently large battery, focusing optics, and an emitting surface at the focal plane big enough to dissipate the waste heat. This sounds a lot like a small digital camera with the sensor removed and an IR LED array put in its place.
Anyone aiming such a device across the venue would be extremely obvious, as everyone else’s inadequately filtered camera would see it :)
Right, because people looking through their cameras at all of the chaos, flashing lights and pulsating wristbands would _definitely_ notice one human being standing there with an IR transmitter and be able to understand what they were looking at.
I think at least a few photography nerds would notice the 30W white blob coming from where you're standing. Now whether that would get you in trouble...
They already have an even more powerful IR spotlight sweeping over the stadium; if that isn't ruining the photos, then I doubt the attacker's 30W source would even register.
Can confirm that everyone there is taking shitloads of photos and videos with their phones and I've never seen the stadium IR emitter appear in any of them.
The battery to run a 30W thing and the cooling required to dissipate it would look much closer to a large hand flashlight (the 3kg ones, with the handle) than a camera.
A single 18650 can do much more than 30W. My Emisar D4v2 can pull ~17A from a single 18650 on turbo mode, and it's not much bigger than the battery itself. I carry it on my belt everyday. It starts to get a little uncomfortable to hold and eventually triggers the thermal protection after about a minute of continuous turbo use, but that's more than enough for a quick prank. It runs an open source firmware too, so I could theoretically swap in some IR LEDs and program it with the appropriate modulation.
Anyone aiming such a device across the venue would be extremely obvious, as everyone else’s inadequately filtered camera would see it :)