Isnt part of the whole point of SARTIME logging to reduce staggering costs of searching a whole district looking for an aircraft been missing for a long time?
Less participation will result in increased risk of un logged prang.
The entire cost of the few uncancelled sartimes would be burnt in the first few monutes SAR flight looking for them
Education and technology could go a long way to reducing nuisence cancellation errors. Maybe system can send a “meeting request alarm on sartme placement?