No, it's generally true. The rule of thumb is better stated as:
Until after your domain is purchased, or you know who the current registered owner is, the domain you are shopping for is a closely guarded secret, more valuable than a master password.
Assume everyone (slack, msteams, your browser extensions, your firewall, your corporate VPN, your co-worker's electron apps) is snopping on you and will get a commission for leaking your domain to the fronting groups.
Domain squatters charge a minimum of that's at least $2000.