Legally, as several people have pointed out, there isn't any question. The law is what is.

Morally and philosophically, I'd have to say I would support the cop's decision. Where you can drive, so can someone else. You might not be the only bog-driving enthusiast in that grid square, even if there's no one else in your field of vision. For example, what about your hypothetical cop who happens to be patrolling the back country?

Also, at some point you will be leaving the bog and driving on the road. Unless you intend to stay with the mosquitoes until all the alcohol leaves your system, you will be a danger on the public road, and that doesn't mean being pissed out of your mind. Measurable impairment can begin as low as .03. The legal limit in Canada is quite generous.