I have never heard of an app, you could always just not give them your phone!!!
Bob
__________________
My phone history:
2110 - Bit of a brick
5110 - Face Changer
3210 - My First Games Phone
6210 - Almost Everything I Needed
7650 - Groundbreaking Stuff
Setting the phone to autolock in 1 min maybe too much. Set it to an hour or 30 minutes. Besides, if you're gonna put down the phone, then you could just Press the power button once then select Lock Phone.