Thanks for your bug report. The /alias command was added very early on in the scripting language and it appears that, at the time, someone requested that it hide output if it was called from a script but show output if it was called from an editbox. It is a bit of an anomaly because it is the only command that does this (I think). Unfortunately the method for determining the editbox/script state has changed since it was added, so when you use //alias in an editbox it thinks it is being called from a script and hides the output. I am going to change the alias command so that it works like set/inc/dec which hide output by default but support -s to show the output. This probably makes the most sense.
