http://enduro-mtb.com/en/veloeye-uniting-community-counter-bike-theft/
..so you have had your bike nicked and it has one of these non removable stickers on the frame which anyone with a QR reader can then check with their smartphone to see if the bike is stolen ..what is to stop the thief from simply putting another sticker of their own choice over the top and rendering it obsolete?
Or am I missing something ?

Aye, decent lock and more sensible thought into securing it, etc. Most of the thefts I’ve seen have usually been because they’re easy to nick, not because they’ve got a decent lock or shitty sticker.

Thread title largely correct, yep.

Surely a public database of frame numbers would be better. Not removable without being suspicious, and would be easy to check. The prospect of accidentally buying a stolen bike is why I refuse to buy second hand so something is needed!

A bit of Acetone normally removes the ink from most stickers rendering it useless as well.

Some people will still buy into it I imagine.

Depends, thieves aren’t usually that clued up, otherwise they wouldn’t be seeing stolen bikes on ebay/gumtree.

trust us, when it is on, it’s not going anywhere!

Unfortunately I don’t trust them – I’m betting it’s the work of minutes if not seconds to make the sticker unreadable, and I’d be very surprised if I couldn’t mostly remove it.

Once applied, the stickers are near impossible to tamper with

I think I’d want better than “near” – though in any case the “tamper” and “tamper-proof” wording leads me to think they’re re-using existing technology for a different purpose without understanding it properly. My experience of “tamper-proof” labels is that they get destroyed in the process of removing them and you can’t reapply them – so they’re good for putting across openings or screws as proof that something hasn’t been tampered with. It doesn’t mean you can’t remove them.

As above I’d have thought that frame numbers were a good place to start and quite a few forks have serial numbers engraved onto them too (even my rigid carbon ones do).

You used to be able to buy some sort of transponder about the size of a grain of rice (similar to ‘chips’ for pets I’d imagine) which you stuck somewhere inside your frame with a blob of epoxy resin (I put mine in the downtube just above the BB shell); they were about as tamper proof as it was possible to get.