I've often found myself subject to this tactic, where someone will present an argument in support of a particular outcome, and then dismiss any criticism of it because the critique fails to solicit immediate, specific examples.
This is often deployed within an informal or unanticipated meeting, meaning the other side of the debate will not have been briefed or be expecting the points made.
As a working reference:
Person A: I think we should grow less corn this year, as corn hasn't been selling as much as it used to.
Person B: I think that may be short sighted, as market trends can fluctuate and we may find ourselves selling out of corn.
Person A: When have we last sold out of corn?
Person B: I don't have any specific dates to hand, but even in my very recent experience I know we've come very close.
Person A: You don't have any evidence to support that statement; the motion passes.
For major decisions there will be enough time for due diligence, but when Person A holds a senior position and the tactic is employed in informal circumstances, with regularity, it removes the opportunity for discussion. It's basically refusal of response, but via dismissing the lack of evidence out of hand.
Best Answer
Person A is using a fallacy, namely "argument from ignorance"