What do you mean,
February of last year [webmasterworld.com] is "too old" for resuming the discussion?
I've been studying headers with a view to massively reducing my htaccess file*, and inevitably OrgProbe came up. Here's the part I can't figure out, and maybe someone else will know:
If the purpose of OrgProbe is to find out whether your site is blocked by an assortment of ISPs,
does it make any difference whether you block them or not? (Or "poke a hole for them or not", depending on perspective.) Aren't they just testing whether the request gets made in the first place?
* It's early days yet, but a 90-95% reduction in filesize does not look impossible.