Security on VKontakte.

Just today, I was asked how to make multi-line statuses in one little-known social network .
They asked - it is necessary to answer. Well, okay, it is a simple matter, wrote a simple javascript. Everything worked.
I decided to share with less educated comrades and laid out the script in My Notes.
It was a surprise that after this the script refused to work. After a brief inspection, it turned out that everything is very simple - VKontakte replaces some Russian letters in the javascript word.
Began to look further in this direction. Found that the letters are removed from the words DELETE , DROP . VKontakte did not react to everything, both cheekbones and other perversions.
So I just wondered what it was? Such original protection? Why is it needed?
What do you think about this, dear habracheloveki?