Yes, when you use a programmer, you modify your ECM. It logs it and they can verify that if they check it.
GM isn't the only company doing this. Neighbor has a blown Mazda 3 that he changed the tuning on and it backfired, now looking at $5200 to repair, and warranty will not cover because he modified the computer. I know of two others that are also having issues with warranty, but don't remember offhand what they are driving.
05 2500HD CC LB LLY, 4x4, 3.73s 235/85R16's, webasto cab heater, to keep it warm.
03 Buick Rendezvous - When you average over 80 miles per day driving around, you need one of these.
85 K-5, 6.2, SM465, Rockwell T221, 1 tons, 36's. More goodies to be installed as time and money allows.
82 K20, 6.2, SM465, NP208, stock except for bed rack, snow plow, and glow plugs are on a toggle switch. It works great for plowing!
72 Postal Jeep - Yet another project