Validated or not there are still many cases where this is a valid key and thus completely breaks the object. For example, this might be a login name, most peopl

Validated or not there are still many cases where this is a valid key and thus completely breaks the object. For example, this might be a login name, most people would consider it unreasonable to not allow js keywords as logins. For a simpler example, imagine a dictionary of syntax highlighted words for js ;) There are workarounds of course, but the ironic result is that when you want to use a js object as an actual hash/dictionary (something we are repeatedly told js is great at), your code devolves into a defensive programming mess, requiring constructions like Object.prototype.hasOwnProperty.apply, etc.