OTOH, I can think of several instances of covered-trigger holsters being involved is silly accidents.
Here, for instance. Or several incidents here. And one here.
First link does not mention anything about whether the holster was covered or open. Second link has many incidents, none of which mention whether they're covered or open. Third link has one incident, which also does not mention whether the holster was covered or open. Most of these incidents involved guns which were either unholstered or being unholstered/reholstered at the time of the discharge, and as such have no bearing on this issue.
Even assuming every single one of these holsters had a covered trigger, only ONE incident is listed (in the second link) which may have relevance here:
Aug. 17, 1993: Officer shoots another officer in finger when gun goes off in holster as he exits patrol car.
The ONLY way that such an occurance could have happened is if the trigger was pulled by something, and that cannot happen if the trigger is covered by the holster, unless the holster itself is defective. As such, either the officer lied in the report and was fondling the gun when it went off, the holster was open and the trigger got caught on the seat belt latch (or some other foreign object), or the officer was using a defective covered holster.
Also, keep in mind that the vast majority of service/duty holsters cover the trigger guard. Thus,
any incident is likely to have happened with a covered trigger holster, regardless of the cause. If you were to look at the per capita incidence rate of holstered discharges between covered trigger holsters and open holsters, I'd bet money that open holsters have a far higher incidence ratio.
. When a round exits the barrel it will make a noise, how much you hear is what the supressor does! 
. I say how??? 
