[craze3]

This happened to me with GoDaddy and Namecheap before, which is why I switched to using Gandi for all my domain searches... Now I'm regretting it!

But as @Jasper_ said, this could be a problem with the domain name registry selling/leaking that info (AKA all their 'is_available' queries), and not the registrar.

[snapetom]

At one point, I believe a GoDaddy VP was doing this as a personal side business. For many reasons, GoDaddy is the shadiest of them all.

[Hoasi]

You shouldn't regret it. GoDaddy was and still is way worse than this, there is no comparison.

[albedoa]

I was always told that Namecheap does not engage in this practice.

It's a single data point, but I instructed a client to search for domains on Namecheap last year since they were undecided. I just didn't want them to use GoDaddy, and I warned them why. They settled on a domain but registered it months afterwards. It was still available.

[benhurmarcel]

I have the same story with Gandi. Searching for a domain (several times even, on a .com) and was still available months later.