Basically me and my friend are not from burgerland and live in a country with pretty bullshit hate speech laws. He uses a vpn to post online but has a habit of flexing his impulse purchases on sites like twitter and reddit (watches, headphones, pc parts, peripherals, albums) with his handle. A lot of these things are niche and only sold by some specific websites here.

We had an argument where I basically said if anyone wants to track him, they can just contact the handful of websites that sell that item and easily track him using some basic breadcrumbs. He thinks I am being overly paranoid and something like this is not possible. Is there any case where this scenario played out?