Since workspaces are probably tied to custom domains all they see if only cursorly looking are "random" businesses with bounces (as TFA mentions, Gmail addresse

Since workspaces are probably tied to custom domains all they see if only cursorly looking are "random" businesses with bounces (as TFA mentions, Gmail addresses seem to work fine), sure if you look closer you'll notice the MX might be a google one but going from the cursory look to a closer one takes a bit of time.