Currently the Get-VIEvent cmdlet only returns for the entity mentioned on the Entity parameter.
This means for example, that it only returns events for the cluster itself when a cluster object is passed on the Entity parameter. It does not return events for all the other objects, like for example VMs, in that cluster.
The underlying CreateCollectorForEvents method does provide an option in the EventFilterSpec object to recurse or not.
Externalising this option to the Get-VIEvent cmdlet would avoid that the user has to specify all entities explicitely. And it will make the cmdlet faster.