What is better for your reptile, day basking bulb at night or no bulb at night?

I work at a pet store, and we ran out of our night time bulbs and a couple habitats are burned out. I instructed my employees to just leave them be since the store temp. does not drop under 70 degrees they will be just fine. and they need a coolness cycle ociated with night time. well, another employee on the same level as me decided it would be best to put a day basking bulb to replace the night one, giving them a 24 hour day cycle. Now, i am pretty darn sure what i told them to do was the right thing to do, and that a 24 hour day cycle is more harmful than going without an additional heat source at night. what are your opinions?