Defend herself how exactly?
Take the example of a daily occurrence, Turkish jets overfly Agathonisi island. The event lasts a few seconds, the island is tiny. You shoot down the offending jet and it will fall in international waters, and you have zero support from the international community (who supply you with spare prats etc).
There is rarely any violation of air space which can be answered "dynamically" in a way which will provide unequivocal proof of a violation. On the rare events when there was such a violation, ie in eastern Crete and over Skyros, the outcome was not a happy one for the offenders. Same goes for the cynical exploitation of the rules of innocent passage. But when a sub violated the rules it was forced to choose between surfacing and identifying itself or running out of air. So the response is not as limp wristed as it looks.
It would be helpful to take a look at the map and see the length of the line of possible conflict, it stretches from Ormenio in the north to Kastellorizo in the south and inevitbly would extend to Famagusta if things get rough. Upping the ante involves being rady for a clash along a thousand mile line of confrontation. It is not a decision that can be taken lightly.