I wonder if they were betting the case couldn't be x-rayed. Our xray controller PCs can't, but the case is 1-1.5mm thick steel on all sides, which does tend to make your average dell look like tinfoil.
(Found out about this when taking a repaired unit back to Birmingham Airport, going airside, the controlled appeared as a solid blank square on the xray machine we had to go though to get to where our xray machine lived!)