This is absolutely ridiculous. 24 hours of bright light while not ideal isn't going to harm the snake, whereas an unregulated UTH could easily hurt the snake plus the fact that it is a fire risk.
Thickening the substrate layer is never recommended when using a UTH. BP's are known to dig into the substrate and sit directly on the bottom of the cage. By thickening the substrate you also risk increasing the temperature of the glass.
Lamps even white lamps are the way to go in this situation. If it was going to be more than a few days I would recommend getting an infrared heat lamp but even then a good BP cage should have a nice dark hide anyway.