Why don't you just call them out anyway if its so much of an issue you not knowing. It is by far the safest option compared to not calling them out and leaves the crew in peace to fly the aircraft.
And I didn't intend to imply that its is acceptable to not declare if there is a problem. But it is an issue in quite a few cultures. Its not helped either that if you do declare in quite alot of places outside europe you will be issued a bill for the energency call out and the aircraft won't move until its payed. Sometimes the bill is not even to the company either its to the PIC.