Adam Bertram explains terminating versus non-terminating errors in Powershell:
Non-terminating errors are still “errors” in PowerShell but not quite as severe as terminating ones. Non-terminating errors aren’t as serious because they do not halt script execution. Moreover, you can silence them, unlike terminating errors. You can create non-terminating errors with the Write-Error cmdlet. This cmdlet writes text to the error stream.
You can also manipulate non-terminating errors with the common ErrorAction and ErrorVariable parameters on all cmdlets and advanced functions. For example, if you’ve created an advanced function that contains a Write-Error reference, you can temporarily silence this as shown below.
Adam also shows how to convert a non-terminating error into a terminating error in your script.