that's largely not what motivates law enforcement's choice (prosecutors aren't generally the ones choosing the testing laboratory; it isn't what motivates them,

that's largely not what motivates law enforcement's choice (prosecutors aren't generally the ones choosing the testing laboratory; it isn't what motivates them, either); keep in mind that contracts have to go through the accounting/legal department. they care about cost, and turn around time. availability to answer their questions, and some level of treating them with basic respect are up there, too (by "basic respect" i mean avoiding things like "i don't have to explain shit to you, you're a dumb cop and i'm the fancy scientist"). if you're regularly telling the DREs that they're wrong, you're going to have some arguing/explaining to do, but it is unlikely to lose you the contract. the labs that go rogue usually do it for stranger self-motivated reasons than "gotta give the cops the exact results they want"