If you don't want other people borrow your phone for SMS, you can use this trick to do.
- push *#MOSMS# or *#66767#
- then you choose MO-SMS off
Now you try to create an SMS, it lost isn't it?
If you want back it, just take steps above and choose MO-SMS on and it will apear like before.
Try It!
Note: It work for Nokia CDMA: N3585/6, N2115/6, N6585 ect