Well to be fair for all we can prove any player ever could have map hacked in some online tournaments.
Nerchio could have map hacked not once in his live or 5000 times, there is no way of ever telling 100% unless you have prove they actually hacked (and I'd imagine they'd be smart enough to not make it look too obvious).

At the same time, lots of people who used to map hack in bw are well respected on tl nowadays so even IF nerchio hacked, from the past I don't see how our community would punish that long-term anyways (not saying I'd be okay with it, just that from our past mher are usually forgiven).