1) Find list of people who you don't like (in this case, for legally donating).

2) Perform illegal searches to find things they have done which are illegal.

3) Find another excuse to perform a nominally legal search ("His tail-light was out. I smelled pot, and when I searched him I discovered a large amount of cash in his wallet.")

4) Arrest him for the activities discovered in 2, but allegedly discovered during 3.

tl;dr: Parallel construction allows for politically motivated searches which can lead to 'unrelated' convictions. You will never even know it happened, you'll just be cursing your bad luck.