I'm sure it is different in many states. I'd suspect that it's also sort of based on the amount of time they have available to do it in. In other words, during the height of the recession, I suspect they weren't being overly concerned with doing follow up contacts on their initial decisions, as all quality and benefit accuracy measurements sort of went by the wayside.
But when some employer gets the notice that during this quarter Joe Blow drew unemployment insurance charged to their employer account after Joe Blow was fired, they tend to raise heck and announce that they never got the notices and that they never received their promised opportunity to contest the claim. And sometimes, if there's no record of a follow up call or contact attempt in the claim history, they get a do over (at the state's expense, not the claimant's).
And I still emphasize, if you do not want to contest the claim, that's one thing. But not contesting it, even telling the unemployment agency you don't want to contest it, does not necessarily guarantee that Joe Blow gets approved for benefits. If the employer wants to be sure Joe gets to draw benefits, they need to give him a lack of work separation.
If he tells the unemployment system the circumstances of his termination and it sounds to them like old Joe richly deserved to be canned, they could very well decide he didn't qualify, even without the employer's feedback. I've actually seen this happen, when Joe tried (unsuccessfully) to firebomb the office, and the employer was concerned he would retaliate if they fought the claim, and they specifically stated that they did not want to contest the claim. But Joe was terminated, and he proudly came in and confessed his wrongdoing, told the claims taker how he showed that jerk a thing or two, told him where to go and then there was that little episode with the firebomb! Guess what? Joe no draw. We made it a point to tell him it wasn't his employer's fault, it was his.
But this OP seems to be one of the master overthinkers of the universe, and he'll parse and re-phrase and agonize over every aspect of this issue until he gets another job anyhow. I think he has a pretty good chance of approval, whether the employer responds or not, but he seems convinced that they have to fail to respond or he is in danger of being disqualified.