Several elements went into the success of this project. Although we didn't do a formal SWOT analysis beforehand, in retrospect it's clear what the Strengths and Opportunities were:

• There was a small, well-led, harmonious team with tons of energy and abilities, and just enough budget to hire pro-level video, PR, and coaching.
• The team had a tightly-focused campaign with a straightforward ask: get Starbucks to drop their vegan-milk surcharge (fitting into their larger campaign against dairy).
• The team had a new angle: that the Starbucks dairy-free surcharge amounted to dietary racism — "a social construct built by a racial majority that assumes the food the majority consumes affects other races and cultures in the same way" — because only people of Northern European descent can generally digest dairy.
• The target, Starbucks, was particularly vulnerable because of its pretense to being "progressive." (The idea of choosing a target for its vulnerability was well exemplified by the campaign against PNC bank, in which activists chose that particular bank because of its business model of reaching out to students.)
• Starbucks has many outlets, and so one could do interesting, funny things there — along the lines of the fake police-violence vouchers redeemed at McDonald's. (There was in fact a whole hidden-camera angle to this project, but the footage wasn't used in the reveal.)

As for the Weaknesses and the Threats:

• The initial team was all white, and so a campaign around dietary racism could be exposed to charges of using race instrumentally for other purposes. 
• The day chosen for the announcement, in mid-December, was perilously close to the holidays. If something else had dominated the news, we would have had to defer our launch until after the New Year.
• If Starbucks had preemptively removed their non-dairy surcharge before launch, the campaign's goals would have been served, but only partially: there would have been less spread for the concept of dietary racism, and possibly less pressure on other companies.

The campaign could claim several victories.

One was the actual dropping of vegan milk surcharges in the UK — a remarkable success for a stunt that took such a small team and budget to make. (See this wonderful interview with Switch4Good founder Dotsie Bausch for more.)

Another victory was the addition of the term "dietary racism" to the vegan-activist lexicon.

For us Yes Men, the biggest victory was the sustainability of our involvement: all we did was coach, and for a limited number of hours. We basically:

• suggested a model, Coal Cares, a project of ours from 2011 that drew attention to under-publicized information;
• suggested elements that had succeeded in other previous projects of ours and of others;
• helped brainstorm brand-new angles and elements that we thought might be fun;
• pointed out pitfalls before they could be fallen into, and encouraged the team to preempt potential threats; and
• helped overcome legal worries, in part through braggadocio and in part through concrete legal introductions.

In other words: we didn't do very much!

This project proved yet again what we've been saying for years: all it takes is some organizing, an achievable goal, lots of energy, and at least a theory of change to pull off a trickstery victory.