Live rock on eggcrate, sand or on bottom?

[lastlight]

Putting it right under the rock isn't going to protect your glass if you were to drop a piece somewhere else later. So why bother? It's also bound to get exposed and looks ugly. Biggest reason in my mind is wrasses though. Mine dive full speed into the sand and move pretty fast under the sand finding a sweet spot. They're clearly hitting glass and then sliding along it. I can easily see them getting beat up doing this on eggcrate.