I'm putting my six months old baby mostly on the bed, very very rarely on the floor as she tends to fall while turning and trying to sit. Till date sh
So if you put on the padded floor (with carpet/rug) on a mat, you must sit with the bab y and support her sitting with cushions (pillows)! Babies at this age SHOULD NEVER BE LEFT ALONE UNATTENDED!! If you are sitting with her, she won't be falling or tumbling because you will be able to support her!
There's no justification.... If the baby is falling on the floor, he or she can fall on the bed as well. I'm thinking your baby is not yet able to sit WITHOUT SUPPORT!!