Because fuck you, the whole system is rigged.

A cop that planted evidence on you would then, usually, find that evidence to announce that you had it.

That finding action would likely excuse any fingerprints on the evidence unless they were extremely careless and left a fingerprint inside the baggie.

Cops wear gloves when “searching”

Besides all the other arguments, fingerprints aren’t like the movies. You need a reasonably flat surface to get a fingerprint from.

Getting a fingerprint from a house or a car to prove that someone was there at some point, any time in the past, is possible. Getting a fingerprint from a plastic baggy to prove someone held it would be much harder.

The distortions would make it extremely hard to match against a database. If they compare it to you then it might show a match, so if you’re a suspect they might make a direct comparison. If they compare it to the cop? Remember the cop is innocent until proven guilty, so they can’t compel them to give fingerprints for comparison. Yes, they could be in a database, but remember the distortion makes it hard to automatically find this.

Any lab work has a cost, and police are lazy. They aren’t going to spend time or money trying to solve a case. They go with best effort.

I think the point OP is making is less about the cop’s fingerprints and more that your fingerprints would be missing. Might at least introduce reasonable doubt if you are claiming they were planted.

You don’t get to make requests lol

The problem is that the container is evidence.

Even if planted, what does a cop do with evidence? They take it from the person. They’ll usually do so with their hands.

If they’re not wearing gloves, they can still explain away those prints by dint of touching them while taking them as evidence. If they’re wearing gloves, the only way they’d leave prints is if they weren’t while they were getting the container ready, but then they can still claim to have handled it without gloves at some point

It’s an impossible to prove claim unless there’s other evidence supporting the claim.

Since most court systems default to a cop being a credible witness instead of them having to back up their claims with other evidence, you’re fucked.

So it’s a bad defense. To make it stick, you have such a barrier to break down just to try to gain supporting evidence that you ain’t gonna be doing it from jail unless you’re rich.

Not that nobody tries. They do. It’s essentially a waste of time, but people will claim that evidence is planted. It’s just extremely rare for it to work, even when there is supporting evidence. It’s also a trope, so getting a jury to believe the claim is hard. You see it in movies and shows so often where the hero cop arrests someone with drugs and they say that it isn’t theirs, it’s planted.

Copaganda is a thing, and it works. Because it’s such a common trope, people have the idea that it’s something only claimed by people that are obviously lying. It doesn’t help that if you’re the kind of person to take the claim seriously, and take the other evidence into account, there’s a lower chance of you being on the jury. Jury selection, any prosecutor is going to ask questions that will find folks predisposed to a bias against their case. Same with defense lawyers wanting to exclude those against their defense

That’s not exclusive to drug cases, but drug cases are such that it’s easier for fake evidence do be planted. It’s very hard to fake a weapon in a murder case because testing can be used to exclude things. But a bag of drugs? Much easier to fake things. Hell, a cop wanting to do it, all they have to do is wear gloves, then push the baggie against the hands of the person, and now the planting claim is harder to prove