As far as I can tell the only problem with offsets is that it's difficult to account for. If you buy offsets for 1 ton of carbon, it's difficult to ensure that the offsets represent carbon that would actually be added to the atmosphere if not for that funding. Is your comment just extreme pessimism about the efficacy of the auditors or are you remarking that one can't offset their carbon (i.e., co2 isn't fungible)?