It seems there's actually two discussions going on here
1. Can we spin the Jab under RA-Aus?
Answer: no, because of the regs. Easy, clear, nobody's going out today to spin their Jab because we're all not stupid.
2. Is the placard worded wrongly?
My Answer: yes, because it leaves the manufacturer open to liability if someone does die in an unintentional spin.
Orion, yes if you spin and die you will be dead and not care what the placard said, but your family and Jabiru will care once the court case starts because there is inherent ambiguity in that statement. There is a potentially arguable implication that if you do spin it unintentionally then the aircraft will be able to handle it which leaves Jabiru open to potential liability.
There is definitely an arguable implication that, if you unintentionally enter a spin, then the aircraft will survive
If the manufacturers knew that there was absolutely no way ever that the aircraft could suvive a spin then the placard would probably say NO SPINS EVER ON RISK OF DEATH or something. But putting in the word 'intentional' leaves it open to argument should a court case ever arise on this matter