jon, 
Now I am trying to get my head around luggage scans on Eurostar trains
Channel Tunnel security is determined, UK side, by the Channel Tunnel (Security) Order 1994 - PDF https://www.legislation.gov.uk/uksi/1994/570/made/data.pdf
This stipulates what is not permitted in terms of behaviours, but not that every single bag on a Eurostar has to be controlled
Could theoretically an operator not choose to control every bag?
