If you are asking if you could use eggcrate as a structural part of you aquarium stand, i would say absolutely not.. If the top wood on the stand looks questionable, replace the wood, and add a new piece (of wood) to the top of it. I would never use it between the tank and stand as any type of support.
I will tell him that, but he also asked about putting a 20g long on his fireplace. He says he never uses it anyway and it looks stable.