Routinely, I find issue with people's inability to provide evidence for their arguments, coupled with a reversal of burden. Perhaps laziness incites this. Perhaps ignorance incites this. Nonetheless, it is ineffective argumentation. Let's look at a couple examples I have encountered:
Since your OP enumerated failings of Democracy, it would be more instructive for you to offer a system that you think has proven superior.
Stronn, who failed to post anything of substance in that thread, suggests that because someone claims Democracy fails, that an alternative system needs to be proven superior. It is not mutually exclusive that (1) Democracy fails, and (2) every other system fails.
Or, you could show us how OkCupid does not attract people who wish to engage in casual sexual relations. Why is it that you believe this site to be an exception?
Zeichen also engaged in this logical fallacy. When she agreed that a "willingness to engage in casual sexual relations is the intention of the [OkCupid's] users", I asked for evidence. As quoted above, Zeichen attempted to flip the BoP by suggesting I had to prove something else, as if that had anything to do with his bare assertion (quite a dishonest burden reversal, and one I suspect was made intentionally).
Have you too encountered this reversal of burden?