firewall -
Not that I know or have any info - but I don't see why it wouldn't be possible for them to quite easily track our Id travel through the Id travel bookings and payment systems?
Nothing to do with immigration.
As you know the effort is being made right now to go through the last few years worth of ID travel for all pilots to find guys that have started duty without adequate rest after commuting - several people have recently been in trouble over this - and a few more are about to get punished for past sins as they are found out....