Your problem is related to scoping - variables created (assigned w/ an explicit scope qualifier) inside a function cease to exist after the function exits.
If, when you assign to the variable, you use:
$script:DisabledRequest = $true
Then you'll see what you expect. For more information about scopes, you can read the topics from built-in help 'about_Scopes' and 'about_Variables', available online here: http://technet.microsoft.com/en-us/library/hh847849.aspx and http://technet.microsoft.com/en-us/library/hh847734.aspx.