I think that an alkaline AAA cell has a capacity of about 1 amp hour.
Therefore if there are two of them, the total amount of energy is 3 watt hours. While these could, if short-circuited (especially if they were connected in parallel as this would reduce the internal resistance) produce enough heat to set something alight, I would think that the normal load would hardly be enough to produce enough heat to do any damage. Most semi-conductors which produce any heat are normally mounted on heatsinks which tend to disperse it and I'd be surprised if there are any resisters less than about 100 ohms to heat up (3v across 100 ohm would produce less than 1 watt - the heat of a torch bulb).            

Incidently Steve, I used to have a battery-powered valve radio which worked on a single battery which produced both a 1.5v heater supply and a 67.5v anode supply. There were whole families of valves made for these things and my first amplifier was based on battery valves as my dad wouldn't let me use mains power until I was older.