I think the reason was this, though as I've only browsed the Mark1 Mod 0 Rulebook, and don't own it, so I may be in error:
Wilds Governments were introduced in the Mark1 Mod 0 Rulebook, but not the Wilds Allegance codes (or maybe they were left out of the Subsector Data). Thus the only way of knowing if a world was definitely a Wilds Government was if it was mentioned in some text referring to the world. Having a Subsector Map was good, but not perfect as there were a significant number of non-Polity worlds in Diaspora, and a few in the OE (too few?), that used the normal Government Codes.
The Mark1 Mod 1 Rulebook fixed this simply and elegantly with the "Wi" alegance code, the HIWG suggestion (which Don appears to have taken for Mark1 Mod 1 Errata) was to re-convert Wilds Government Codes to normal Government Codes, with a small chance of having a TED, with that being reflected with a 'Td' in the UWP comments.
Eamon
From: "" <>
To:
Sent: Thursday, 14 June 2012, 22:49
Subject: Re: [Traveller_TNE] Question for the group
Aaaahh, yes. NOT "Wilds" allegiance codes as I was thinking, but Wilds
government codes. I remember now we had to do that, but the details elude
me at the moment.
On Thu, 14 Jun 2012 14:38:22 +0100 (BST), Eamon Watters
<eamonwatter