As I was updating the latest MTR for the Android judge app, I noticed that:

10.4 Pairing Algorithm

Unless otherwise announced, tournaments are assumed to follow the Swiss pairing algorithm. Some tournaments may proceed to single-elimination playoff rounds between the top 2, 4, or 8 (or other number) players after the Swiss rounds are over.

…

For Premier Events, the playoff options above are required, not optional.

Going further down to:

Appendix E—Recommended Number of Rounds in Swiss Tournaments

The following number of Swiss rounds is often required for Premier tournaments. It may be used at the Tournament Organizer’s discretion for non-Premier tournaments. It is included here for reference only.

Players / Rounds

8 / 3

However, on the official Wizards site for PPTQ Milwaukee:

http://magic.wizards.com/en/protour/pptqmil15#tabs-3

Number of Swiss rounds and number of players that advance to the playoffs is based on attendance according to the following chart:
Attendance Swiss Rounds Playoff
8 3 Rounds (Single-Elimination Playoff Online None

So, the question is, in the freak event that I have only 8 people turning up for a PPTQ, or GPT (as I have witnessed it happening for GPT more recently here), do I go with a single-elimination format or do I follow the MTR/WER with 3 rounds of Swiss into Top 4? Fingers crossed that I never run into an 8-man PPTQ, but, it's better to be prepared I guess.

Edited Andrew Teo (March 24, 2015 12:38:17 PM)

The fact sheet of an event overrules MTR (and other documents like PEIP).
The fact sheet says 8 players –> 3 rounds Single-Elimination, so this is the way to go.

If your GPT or PPTQ has 8 people, you run it as single elimination.

"The *Magic: The Gathering *Tournament Rules
<http://wpn.wizards.com/en/document/magic-premier-event-invitation-policy>
and the *Magic: The Gathering *Infraction Procedure Guide
<http://wpn.wizards.com/en/document/magic-infraction-procedure-guide> are
in effect for this event unless specifically overruled by information in
this Fact Sheet."

http://magic.wizards.com/en/protour/pptqmil15 (PPTQ Milwaukee Fact Sheet)
http://wpn.wizards.com/sites/wpn/files/attachements/wpn_gpt_rules_en_jg.docx
(GPT Fact Sheet)

Cheers,
Adam Hubble

Oliver and Adam are correct.