If it’s stolen they will either recover it or replace it. And everyone knows this, so no one will buy a stolen one and they are less likely to be stolen.
You mean they know the vendor is an infinite supplier of free bikes to steal, deSaaSify, and sell to a different market?
Either way, the message doesn't spread itself; I wouldn't overestimate how much small-scale semi-pro thiefs know or care about bullshit tech startups.
EDIT: the only real advantage VanMoof could have here is if they're selling shitty bikes and overpricing customers for the brand name. That would indeed deter most thieves successfully - by making stealing those bikes not worth the effort. Well, until the metal prices spike or something, and it's profitable to steal them and sell as raw material...
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[0] - See e.g. cheaply available conversion kits for Bird scooters; IIRC they were being sold for something like $30. Though those had a plausibly legal use case: converting decommissioned or seized scooters. There were plenty of the latter, as following the example set by Uber, Bird also pretended law and society don't exist.