What we do screen for a bit is basically time wasters. It is possible to be accidentally picked up in this net, and then say "they sure missed out, I bought a car at the next place". That's unfortunate for the salesperson sure, but you're ignoring the countless hours saved by quickly dismissing the true time wasters.

I sold cars and was very good at it (better than top 1%) and would sometimes get in a mood when I would ignore intuition for a few weeks and just do an amazing job with everyone. Doing an amazing job works well, and you can get people to buy a car who swear they stopped with ZERO intention of actually buying a car that month even, very often. But you almost never even get CLOSE to selling a car to someone you have a bad vibe about, even if you go all in.

If you're good at car sales, you have more people to follow up with and do a good job with than you have time. I sold 34 cars a month average over years. National average is 11. Eventually you have to trust your judgement to save yourself 10+ hours a week, even if once a month it costs you a sale.