I'm currently reading Steve Smith's Men, you might want to pick up a copy.
Anyone who thinks ball tampering has only happened in the times people have got caught (Atherton, Smith/Warner/Bancroft, du Plessis, Murray mints, Chris Pringle 1990 et al) are naive to say the least. The ones who got caught were too reckless, the ones who didn't do it were the outliers. Then Australia were stupid enough to go with a plan hatched by Warner when he was taking his family to Bunnings for a sausage.
Hell, I once played with an international (played a lot of Test and ODI cricket) who completely swapped a ball in the break of a senior club game, for one he'd doctored at home. I also know that fingernails and foreign substances are rife in FC cricket away from cameras.
And which umpiring howlers? I'd suggest McGrath stepping on a ball was a major issue, given he averaged 23 in the series, next best was Brett Lee at 41,and Australia lost that Test by 2 runs.