I haven't seen any notice that I'm required to keep it active for the length of my stay, but maybe I've overlooked something.  Just asking to cover my a$$...

I have never heard of anyone required to show it to any official. Having said that, what does it cost you to keep it on your phone?

I deleted after the Sandbox program. It was killing my battery on my phone Bluetooth on all the time. 

I don't think it's any issue going forward. 

9 minutes ago, HappyExpat57 said:

I have never heard of anyone required to show it to any official. Having said that, what does it cost you to keep it on your phone?

Though I have nothing to hide, I dislike the idea of being tracked any more than I already am.  I haven't found a way to turn it off and as another person mentioned, it's a real drain on the battery.

you can delete it after leaving airport.

Uses bandwidth.

Alternative to morchana is thailand plus. Possibly that one is safe