Big problem - Making our nick words big, forgets chests!

[MorkaZ]

There is a big problem.
When player first time open the chest, everything is ok.
He can't get second time this treasure if I'll not set this, or set forget time.
But.. If he will leave, and change his words to big, or to small if they was big, he can pick again his reward.
Please fix it.
It is making a lot of problems with SMS treasure ranks.
Sorry for my language, english isn't my main.