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My experience matches Nakul's. Technically, Bing claims you shouldn't have canonicals on the canonical page itself, but I've never seen evidence that they actually do anything about that or don't honor the tags. I think they just don't like processing the extra tags. Google originally suggested the same thing, but then softened their stance. I've NEVER seen a practical issue with it on Google. So, by the book, Bing would rather you only put it on non-canonical URLs. Practically, though, it seems to work absolutely fine. I wouldn't lose sleep over it. So many big sites are doing this now that I don't think the engines can devalue the tactic. It's not spammy - it's just mildly inconvenient for them (some extra processing).

SEOJellyfish, There is no way that you can turn off the site, wait 1 to 2 months, turn the site on, and expect to be anywhere near where you were. So, have you asked any more questions around the "testing" they need to do? I am assuming you are an affiliate and not an agency since you state a line between their site and your "campaign" site. Are they just tired of paying affiliates? What do they want to achieve with this? How are they going to compensate you for going black for up to 2 months? What are they going to test? If you do this and the test finishes and you cannot readily regain your ranking, what changes in your relationship? I think I would clarify all of this before moving to turn your site off. Best