Old TV x-ray exposure

[Thyratron]

After just posting a thread in the general topics forum on shoe fluoroscopes (which some of you may remember from years ago), it got me thinking: Many of the old TV repair books caution you from getting too close to the front of the screen when the TV is on. Was this just an "old wives' tale" that was proven generally unfounded later on, or did the old sets actually emit more x-radiation than modern sets do? It seems you don't hear that warning too much anymore.