Sorry to scare anyone but it was just a warnning!
If it is off nothing should occure.
I Had a TI calc with changable battery packs that I forgot to slide it in a carrier one day and got both a burn and a nice hold in my pants . About the size of a quarter... Could not move fast enough to get it out of my pocket.
For this to possibly occure "you would need the unit on" but only a blink to triger the charging circuit. If it touching would heat up the touching object. If a coin would just heat up. If something thin could burn or catch on fire.
The caution came from thinking about the trigger transistor turning on the transistor that feed current to the contacts. If its making/breaking, may not get enough heat to do anything but could drain the battries.
If you have wired directly to the two AA battries to get enough current to the jack for charging could cause problems.
I dont mind anyone saying "you sure" or "your nuts."

This is proabbly about 2% chance but I remember trying to figure why is my pocket hot and how fast I jumped!
I wish they had did the layout that a MicroQ has. Jack on side with antenna on top. Oh well!
I know what you mean of getting that darn car on the jack. Its the pits!