Spoilers seas... well for everything

If the Tyrells had known about how dangerous Joffrey was before they formed an alliance with the Lannisters/Baratheons could they have successfully forced a different arrangement?,

Joffrey wasn't just difficult or prone to starting wars for no reason, there was actually always a risk of him permanently injuring or even killing Margaery, or any future children, the marriage would not give them an equal share in the future of the country.

Now we know how they dealt with it once they found out (I imagine they must have been very annoyed - they saved Tywin only to find out Margaery would marry someone very dangerous).…