I was concerned of an Inventory Ap I had downloaded onto the phone after I put a few items in, so I contacted the people who made it. They sent me a couple emails back and forth. Nice people, but they only made my concern worse. I was just now looking for the emails and so far have failed to find them, but in a nutshell, I asked them how secure the program was (this was pre-Snowden days). They said there was no way to save your data without putting it on the 'cloud', not even your own computer and they said that they could not guarentee that it was 100% safe from other people's eyes. That is when I pulled the Ap off my phone, thankful that I did not use it, other than to scan in about 4 items and did not put the amounts.
So just letting you be aware of what my experience of one of these kind of Aps are. They are definately not OPSEC.