Their patents stand up in court as they have been challenged a few times. Everyone who has taken them on has lost or caved in and the last being TOG as far as I can remember. That was US but it is the same for Europe.

It's illegal to sell largeformat qualified ink to small format users in sublimation. It is illegal for small format printers to use large format sublimation ink. Sawgrass have threatened many time to go after the end user not just the supplier. Plenty ignore the patent as there is a saving to be made but it's the risk you take if you decide to go that way.