In a recent vSWUG presentation, I mentioned that I (personally) would disable all out of the box alerts. Within the Orion database, these are referred to as "canned" alerts and you can do it with a simple PowerShell script (assuming you have the SwisPowerShell module loaded).
<# Disable-OOTBAlerts.ps1 #>
$SwisConnection = Connect-Swis -Hostname 'orion.domain.local' `
-UserName 'Account' `
-Password 'P@ssw0rd'
$Query = @"
SELECT Name
, Uri
FROM Orion.AlertConfigurations
WHERE Canned = 'TRUE'
AND Enabled = 'TRUE'
"@
$Alerts = Get-SwisData -SwisConnection $SwisConnection -Query $Query
ForEach ( $Alert in $Alerts ) {
Write-Host "Disabling OOTB Alert: $( $Alert.Name )"
Set-SwisObject -SwisConnection $SwisConnection `
-Uri $Alert.Uri `
-Properties @{ Enabled = 'FALSE' }
}