The following was posted by a mod regarding this exploit

It was a bug that worked against the spirit of the game, so was removed.
You may have thought of a convenient use for it, but most people were exploiting it in a negative way too serious to ignore.
Regardless of how you feel about any particular glitch, it does not change the fact that it is a glitch.
I have highlighted the part I find funny.

Surely these are against the Spirit of the game yet are never looked at by Evony!

Account sharing
Using a Macro reader/Bot

I can see why people did the Hero/Valley trick and again Evony instead of adapting the game to the changes it's made regarding medals they just ignore the mass players that play the game and the majority that buy cents.

Seriously as someone said increase the medal drop rates again or lower the price of the boxes which are way over priced for what they are regardless if you people at Evony think they are value for money.
Refusal to adapt the game to your changes Evony will cost you customers.

Glad I quit when I did!