Actually I think that tactic has some merit, however...
"There is near universal acceptance of evolution by scientists, and we teach what scientists believe."
An opponent could point out that near universal, means that it is not universal, which logically means some scientists do not accept evolution. And if we are supposed to teach what scientists believe, shouldn't that include all of them?
Then they'd go on about how science is not stagnant, should not be, as once controversial theories go on to become near universal beliefs in the future.
I think the tactic you mention works to some degree to rob power from wholly fallacious comments, or rhetorical tactics to make the incredible seem credible, but wherever there is admitted wiggle room for error true believers (of any belief system) will latch on.
Edited by Silent H, : wherever
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"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing." - Robert E. Howard