How does the force and hide the signup option work?

Hello,

can someone please explain to me how does the

force and hide the signup option by linking to the signup page like this: wp-signup.php?Pro+Site=1

really work?

Placement of redirection:
We can get ProSites to redirect if we put the redirection as a link on any page or post on the site. OK.
But what happens with the widgets? Those links are automatically generated by Wordpress itself. For example on the Meta widget, when someone clicks on "register" is taken to signup.php. The same happens when any auto generated link for a signup is pressed. Is this the expected behavior? If not, how can we change it?
I would expect that: when you say "force and hide the signup option", even auto generated links would be redirected.

Behavior of redirection:
Also, when you say "force and hide", what exactly does it force and hide? I mean whether one clicks the redirect link (wp-signup.php?Pro+Site=1) or the normal auto-generated register link on the widgets area, one ends up viewing the same first page of the wp-signup.php no matter what the link says.The screen remains the same in both cases. Now, after clicking "Gimme a Site" in both cases one is taken to the second page of wp-signup.php. I see no different behavior what so ever. What is it that we force? We get redirected to the same pages and on top of that there is nothing hidden.
I would expect that: when someone is taken to the second page of wp-signup.php the options "I'm interested" and "Not Now" to be hidden, replaced by the ProSites auto generated price tables, have no other option but to register with one of the ProSites packages, and immediately taken to the PayPal account (or whatever gateway option is given).

Am I missing something? Please enlighten.

Thank you