Sure it is. Upon receiving the counternotice, StackExchange can just say "OK, we're no longer have the question offline because of the DMCA notice; as a separate matter we have decided that we decline to host this question". To believe otherwise would be to believe that a DMCA notice and counternotice somehow privileges the subject content above all other content on the site.
But it does privilege that content above all other if the service provider wants the liability protection. You either treat that content specially or you are open to being sued for having hosted it before you took it down. To meet the requirements of the act, they must actually "replace the removed material and cease disabling access to it" (H.R.2281 Sec. 501(g)(2)(C)). Doing what you said would fail to meet that, as would some kind of "it was available for a split second but you didn't see it" prank. Real judges don't take kindly to trying to weasel around the intent of a law.
Just like in many states you can fire an employee for no reason but you can't fire them for a discriminatory reason, you are in violation if you take down the content from the notice despite the counter.
