A forum post from earlier this week explains Blizzard's approach to disciplining Diablo III players for exploiting a bug that granted extra blood shards from treasure goblins. The exploit has been closed off via a hotfix, and they explain they are dealing with three different levels of violation, and their response ranges from banning the worst offenders to pardoning those at the other end of the spectrum:

From there, taking the complexity and impact of the exploit into consideration, we also elected to action accounts on a case-by-case basis. In general, one of three things occurred:

• Accounts which were found to have both used the exploit excessively and publicly promoted its use were permanently banned.
• Accounts which were found to have used the exploit excessively, but did not publicly promote it, were rolled back and their associated heroes removed from active Leaderboards (both Seasonal and non-Seasonal).
• Accounts which were found to have used the exploit to a limited degree (or quickly stopped once realizing the scope of what was happening) were effectively pardoned. We understand these situations can inspire a certain level of curiosity and that it may not always be immediately clear if you’re undermining intended game mechanics. Mistakes happen, but we hope this leniency won’t be taken for granted in the future.