Configuring wpa_supplicant to only scan, not connect?

[JoSH Lehan]

Hello there.

I've had good success running wpa_supplicant, it gets on the air and
associates nicely.

However, there's a situation I'd like to do: scan *only*, without
connecting to anything.

Basically, I want to run wpa_supplicant and gather scan results from
it with wpa_cli.

This works fine, now, with this minimal configuration file that sets
it wide-open, and connects to the first wide-open AP that it sees:

network={
key_mgmt=NONE
}

However, it has the unwanted side effect of making an association, if
an unsecured AP is within range.

Is there a better way to configure it to scan only, and not to attempt
any connections?  I could fake up a random SSID/key that would never
succeed, but that might have other unwanted side effects.

Thanks!

Josh