running computer with side case off

i'm currently running the computer with one side of the case off, not the side where the motherboard is but the other side. is this safe as long as I don't go sticking stuff in there? It's only temporary.

A good airflow works better with a closed case, it should suck in the air from the lower front where your hds are and let it out where your power supply is, so >>3 is right when he says that you killed your airflow :P