its a pity the Tech crew never EVER give up their crew rest seats for families. We all get tired and have a legal entitlement to rest seats but the tech crew never give theirs up
Sorry Pegasus, but that's crap, IMHO.
In my experience, refusal for a tech crew rest seat happens when the tech crew rest is
required for CASA limits, of which there are several complex pages worth to consider, and also when it cannot be occupied for takeoff/landing. It's not just a simple matter of the total tour of duty, and busting them is not an option for us. We have licences which are quite "loseable", remember. In fact not that long ago we operated a 3 pilot crew and all actually agreed to forfeit the crew rest (despite it being specifically set up for our flight) so that a family member could get on. However we first had to check the limitations to ensure that it was not legally required.
In my experience the vast majority (yes there are always exceptions) go out of their way to accomodate both tech & cabin crew family members accompanying operating crew.