fwiw, to be a DEA registered lab, and thus, have known marijuana (or other controlled substances) just hanging around, you've got to keep it locked up such that it requires two people to access it, and you've got to track it (very precisely) by weight. and the DEA can check your records any time. they have caught at least some people (who were "diverting" cocaine up their nose) with this.
I may be talking out of my ass here, but I was under the impression that for weighting, the transport or container will be considered. For things like LSD, this is really idiotic, as the transport (like paper) will weight many, many, times any prohibited substance.
If the same rules are used for all drugs, then adding weight might not require any prohibited substances. Also, a record of something going up in weight may be odd, but probably is less interesting than it going down in weight.
Not that it negates your point. She may have just written down false weights on the data they sent to court.
there should be super careful weighing with, and without the packaging. i'm too lazy to ask my wife who'd know, but i believe that for tracking purposes they include the paper. for sentencing purposes they sample the paper in a couple of places, work out average concentration, and then math math back from there to whatever number is necessary.
going up in weight (by more than the uncertainty of the scales' measurement) is going to be a hell of a lot more interesting to anybody who actually cares, since that can't happen in the normal course of testing. certainly going down is what implies diversion, but it is also necessary for testing purposes.
What is to prevent the chemist from just cutting the coke after snorting some of it. Coke comes in 10% baking soda, goes out 15% baking soda, and who is in charge of figuring that out? The person that did it...
you realize that would help the defendant, if anything, right? perhaps even to the extent of getting the evidence excluded entirely?
(also chemists generally don't want some random guy's cocaine. they know the awful shit street drugs get cut with. once you're DEA registered, you can basically just order pure drugs from the government. that's the stuff that gets diverted, and it's also how you'd up the concentration of a defendant's sample.)
even so, that's why two people are supposed to be present for the handling, and samples should be homogenized early on and then split up for independent testing if the defendant wants it. add on lots of tamper evident tape, etc.
"and the DEA can check your records any time. they have caught at least some people (who were "diverting" cocaine up their nose) with this."
It would be trivial for any chemist to "divert" cocaine up their nose and not get caught if they put some thought into it. As you said, some already do "divert" cocaine up their nose, so obviously some chemists are interested in random guy's cocaine. If the DEA is catching people through record keeping, you can be sure there are some chemists who sensibly doctor the records at the same time.
If the chemist is interested in doctoring lab results to screw over a defendant (rather than get high).... well shit, we already know that is possible, don't we? That is the entire point of this discussion. There is really absolutely no sense in arguing that chemists cannot doctor evidence to send some guy up the river, we already know that they can.
