I asked my doctor about lunch meat and hotdogs. She said she had to tell me it could be bad but that more people have been getting listeria from lettuce then lunch meat lately. Basically always a possibility but very rare.
They say to heat it but I never do. Its more of a taboo for Americans just like eating fish while in other countries, especially countries like Japan, where leaving food out to be ate through out the day or fish is a staple its normal to them. I generally don't follow the food "rules" knowing that they are made due to the idea of it being taboo.
It's OK as long as the meat is heated steaming hot to kill the bacteria. I honestly have been eating lunch meat for the past week without heating it. I believe I ate it with my first and never had issues.