Actually, it doesn't even take 5 minute of manual work on Google.
Just checking to see if a given citation exists, nevermind the actual content, is a simple matching query. If I were a lawyer, the very first thing I would do would be to dump every public listing of caselaw I could get my hands on as a local searchable case index, in parallel with having access to a tool like lexis-nexis or PACER (with recap) for more in-depth research. It honestly should be one of the intermediate steps in an AI bot workflow - validate that the citations exist... and then verify that the citation actually bolsters the argument.
Suggested tools:
https://free.law/recap
https://case.law/
https://www.courtlistener.com/...
If you're going to turn an AI bot loose to generate arguments for you, the very least you can do is check its homework, same as you would do for any supervised clerk, paralegal, or lawyer in training working for you. That it can generate bullshit faster than you can is no excuse for shutting off your brain and signing off on it without even doing the bare minimum of due diligence.
The next level of work would be having an AI bot analyze each case and the citations used for the arguments in each, to generate a tree of citations that can be used to argue in one direction or another. Then depending on what arguments you want to bolster, you can selectively cite the cases that give more weight to your case, and prepare counterarguments in case the opposition has prepared an equivalent set of trees that will cherry pick case citations against your argument.
But forget robot lawyers generating bullshit cases. What I want to see is the robot trial judge (and the robot red team lawyer playing the part of the opposition) that can audit your case beforehand and pick it apart so you can be better prepared before you go to trial.