75 Ohm Terminators why?

[vol.2]

Okay, I have a broadcast monitor that requires 75 Ohm BNC terminators to be put on the monitor outputs.

I didn't realize that I was supposed to do this at first, so I calibrated the monitor without the terminators on. As far as I can tell, the only difference it made was that I had to turn down the brightness a tiny bit. It made no difference in the gamma or color tracking. I used a high quality colorimeter and calibration software to white balance everything, and it tracked *perfectly* without the terminators on it.

My question is, why exactly do I need to use the terminators?

Thanks