I worked on a security team that did this when I left - I taped & signed every USB connection at my desk and checked the signatures every time before I unlocked it.

I must be out of the loop but, how do you sign USB connections?

"Tape and sign" sounds like apply tape and add a signature on the tape that you don't expect anyone else to be replicate reliably.

I think they mean literally stuck tape across the connection and signed that.