Well, I tried this little gem of an idea out. Um, I'm not going to lie and say it was neat in any way shape or form. So if you like neat activities, turn away now! I worked in a daycare that had an actual rice table and I do not recall it ever being a messy activity--weird. I will say that the kids liked to feel, taste and scoop the rice but they really liked throwing rice all over! I thought the blanket would catch most of the rice (which it did) but I did not anticipate them throwing the rice! I don't have anything to combat that. I don't recommend doing this everyday, unless it's a good day to vacuum. It was a good sensory experience for them though and we'll do it again.
Yep, they will try to eat it.