"As such" to mean "like that"

1- On any type of formal school exam, these sentences would not be considered "correct" they are never written as such.....they're only spoken as such.

2- Do not behave as such.

3- Doing things as such will bring about disaster. Try to do things a better way.

I have seen some speakers use "as such" this way. Are these sentences valid? Can I use "as such" to mean "like that"?