There's also measuring and shut-up-and-multiplying the wrong thing: e.g., seeing people willing to pay about the same in total to save 2000 birds or 20,000 birds and claiming this constitutes "scope insensitivity." The error is assuming this means that people are scope-insensitive, rather than to realise that people aren't buying saved birds at all, but are paying what they're willing to pay for warm fuzzies in general - a constant amount.

I don't know who's making that error. Seems like scope insensitivity and purchasing of warm fuzzies are usually discussed together around here.

Anyway, if there's an error here then it isn't about utilitarianism vs something else, but about declared vs revealed preference. The people believe that they care about the birds. They don't act as if they cared about the birds. For those who accept deliberative reasoning as an expression of human values it's a failure of decision-making intuitions and it's called scope insensitivity. For those who believe that true preference is revealed through behavior it's a failure of reflection. None of those positions seems inconsistent with utilitarianism. In fact it might be easier to be a total utilitarian if you go all the way and conclude that humans really care only about power and sex. Just give everybody nymphomania and megalomania, prohibit birth control and watch that utility counter go. ;)