PostgreSQL ... will start squawking about wraparound
   ...
   or the monitoring they had in place

If only there was a tool or service they could use that could monitor log files for signs of problems. (I couldn't resist being a little snarky, the situation seems so perfect.)

All kidding aside, kudos to Sentry for being so candid publicly about their problems. We've seen so many companies avoid providing any technical information. About the best we'll hear in some of these is that the problem was "not terrorism related".