Do you think TSA/CBP is going to check the flash data lines to see if the MCU is scanning the flash internally?
This isn’t a standard USB flash controller… You would need to break the casing and physically probe it to figure out that something was off as far as I can tell. It’s not like the MCU broadcasts that it is scanning to the USB port.
You would have to be hitting the stick pretty hard, not just a normal file scan to notice the timing being slightly too long in a small portion of the scans. The bigger problem would be that the flash drive would be brand-recognizable if it ends up being mass produced that they might auto-confiscate it, and of course the default file that it searches for being known.