name change on eurostar ticket

I travel a lot on Eurostar but I've never been aware of anyone checking the name on my ticket against my passport. Of course, that doesn't mean that it doesn't happen.
Also, looking on ebay and other sites it's clear that there is a market in unused tickets, so presumably it is possible.
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However, section 12 of the terms and conditions of sale is pretty clear:
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12. You may not transfer your ticket to anyone else. Tickets already partly used, or made out in a passenger's name, are non-transferable and may only be used by the person for whom the ticket has been purchased. Tickets may not be offered for sale except by Eurostar International Limited or its authorised agents. If a ticket is resold or transferred for profit or other commercial gain, it will become invalid and the holder may be refused access to the Eurostar train.