If a company offers to take back a cartridge after an "audition" by a prospective customer, what do they do with it then? They cannot re-package it and sell it as new if they are an honest dealer. If Audio Advisor really does allow some in-home trial, I would expect them to also be selling slightly used cartridges; if they don't, I would be suspicious of their new cartridge sales.
Auditioning anything is hard to do. Brick and mortar shops may let customers take home electronics for in-home trials, but cartridges and speakers are another matter because they are so easily damaged in the trial process. I know a shop that allowed such in-home trial for its most trusted customers, but that is rare.
Any kind of in-shop demonstration of a cartridge is also not easy as it takes some time to properly mount and set up a cartridge and there is some risk of damage in the process.
If you can find ANY dealer who can play ANY cartridge from the manufacturer you are interested in, that is about as close as you can get to a real audition.

