Interesting story. I have always been a believer in color effecting thermal radiation.

However with the described test:

"Before proceeding, the maintenance team did a test. Team members applied electrical tape to two of the hydraulic tubes, and using an infrared camera, they measured the difference in temperature between the taped and untaped areas."

The believably of the test results would have been better served if the test would would been between a black piece of tape and a white one.

Also suspect the length of the piping color changed (12 cans worth?) was significant relative to the rest of system, and why a noticeable temp change was the positive result.