Holy carp! Come on guys, did you pass Air Law?
A MATZ is not controlled airspace - you are not "busting airspace" by flying through it. Call on their frequency and if you get no reply carry on, by all means making blind calls and of course keeping a good look out (but you'd be doing that anyway).
And as to leaving a MATZ sized area around every gliding site, well Jeez... On a poor day the gliders will be in the circuit and on a good day they will be many miles further away than that anyway.
The ATZ itself is a different matter though - always treat that as active even if no reply on the radio.