There's a lot of things that can happen when a two-cycle engine has insufficient lubrication. Naturally, the first thing that comes to mind is a scored piston and cylinder, but this isn't always the case (which doesn't stop knee-jerk reactionaries who've been inside a couple saws to scream "That ain't it!").
A logger friend of mine ran almost a full tank of straight gas through his 262 once on a landing by mistake. There was no discernible damage and the saw ran fine for another year. I was a witness to both the gas in the can the remaining gas in the tank to confirm it was straight gas. There may have been a small amount of mixed gas left in the tank when he filled up but it was negligible.
We've run brand new saws at Stihl technical update meetings on raw gas to failure a number of times, with a number of different results.