Like everyone has said already, you don't have to avoid the MATZ, only the ATZ - and it's advisable to make blind transmissions on the published Zone frequency....
However, some stations operate tower only at weekends (those with air experience flights etc). If you know you are going to fly through a MATZ, look up the Tower VHF and if you get no response on the Zone Freq, try giving them a shout... You never know, you may even get a clearance through the ATZ
It's certainly the case at Benson, and used to be the case at Coningsby and Odiham.
Happy flying
