So have data sharing setup for a mate till he sorts out his home internet, currently using a 2degrees sim card in an ipad.  He has used like 30gigs in 20 days so went to disable it and did it via the app on sunday.

Roll around to last night and another 5gigs has been used by something, checked my phone data usage and it was only at 200megs for the last couple of days and my work machine (which also has a data share on it) has not been turned on for 5 days.  So this morning i also removed the data share on my work machine (via the app) and even with it removed i am still getting data on the work machine 2 hours later.

So it would seem that even when the app says the data share has been stopped it has not and still using data.  I have tried to also stop the sharing via text and it just sends back an error.

I will give them a call this morning about it but just an FYI to keep an eye on your data if you turn sharing off as it doesn't seem to currently work.