Unity Ads ShowResult.Failed causes?

When using Unity Ads for the Android platform if the user was using an ad blocker and I tried to show an ad would Unity Ads send me a ShowResult.Failed response, would I get some other error message or no message from Unity Ads at all?

Jason

Im bumping this, as i also want to know the use-cases when ShowResult.Failed triggers. Cant find docs on this.

I assume that:
Advertisement.isSupported == TRUE
&&
Advertisement.IsReady() == TRUE

prior to ShowResult.Failed triggering.