And to answer this, and I was there, we didn't have a block explorer for almost a week, that is when we discovered what happened.
Anybody who mined would have seen the excess block reward payments as "immature" just by doing list transactions (although actually given the high block rate they'd probably mature really fast and just be "received")
Before that, there was no way to know how fast blocks were being found.
Likewise getinfo and current height.
There is no credibility to the argument you need a block explorer to see what is being mined. None, sorry.
seems like there is very little wiggle room to justify the instamine.