DIY SASS Question

["Fred Bell" listeningfor1]

I'm making an SASS and I've noticed that most people utilize some type of hard 
surface, such as metal flashing, to cover the center foam piece that makes up 
the "nose" between the two mics.  What purpose does that piece serve, other 
than holding the foam in place.  I found that contact glue sprayed to a wooden 
back plate does an adequate job of holding the foam in place.  Thanks in 
advance.