Border crossing...
Insistence on checking fresh and frozen foods. Renewed "vigor" when entering Mexico.
Also worth noting, that the prohibition of bringing a desktop PC into Mexico is nation-wide. So far it has been vigorously enforced only at Baja California POE's,
But the ban is federal. Total length of international borders.
The aduaneros point out a brand new PC can be imported if it is less than a month old if the original store printed receipt is presented. The entire machine, including monitor, speakers, and printer will be taxed at 25% rate then a factura de SAT issued.
Even crossing with a valid factura out-of-sight-out-of-mind is the best policy.