[beefman]

Maybe applicants need insurance. If they don't work out, their insurance company refunds the employer their salary and the opportunity cost of their bad commits. This way, applicants get muscled out of the job market gradually by high insurance rates, rather than with a brick wall filter.

[ChristianMarks]

That's not a bad idea at all. But it's unlikely to be very useful for specialized work, unless the insurance is highly specialized, and in that case it is likely to be as expensive as malpractice insurance.