There's looseness around arrays because the API for emitting outputs from commandlets is also loose around arrays. There is just one function `WriteObject` that

There's looseness around arrays because the API for emitting outputs from commandlets is also loose around arrays. There is just one function `WriteObject` that writes the value you give it as the output of your commandlet. If you call it once, then that's your output. If you call it multiple times, then the shell has no choice but to then make your output an array of all the values you write. So if one invocation of your commandlet only calls `WriteObject` once and the other calls it twice, the shell in the first case doesn't have the knowledge that it should've wrapped that one output in an array too. And it can't always wrap commandlet outputs in arrays because that would be disruptive for commandlets that semantically only have one result and so always write only one output (like `Get-Date`). And for whatever reason, they didn't want to complicate the API to let commandlets themselves be able to express whether they'll semantically write only one output or multiple, regardless of how many times they actually call `WriteObject`. Such an API can't be a static attribute on the commandlet because commandlets can have wildly varying output based on their parameters. It can't be an overload of `WriteObject` like `(Object, bool iMightWriteMoreValues)` because it has to work for empty arrays. So it would have to be a separate `IWillWriteMultipleValues()` function probably. Edit: Also explained here: https://news.ycombinator.com/item?id=40874873 https://news.ycombinator.com/item?id=40874873