When you think the cities do you pass to your allies makes them strong enough to stand against AS, don't you think that those cities would also make YOU strong enough to fight AS? And if those cities makes your allies strong enough to fight AS, don't you think that the citites make them strong enough to fight YOU?
I would have loved to keep those cities except they where constantly rioting and without massive garrisons they would have just rebelled back to the seleucids anyway. Force diplomacy keeps the ptolemies from launching suicidal attacks on me. *I dont consider it cheating if it helps the AI*