Yes, the liquids & mushies are to help you heal after surgery. Don't jeopardize your band by eating solids so soon.
As far as the band "preventing" you from eating a whole chicken thigh -- the band needs fill in it before you have restriction. Once you are healed up (4-6 weeks) you will probably have an appt for a fill. Depends on the surgeon you used. Some have a set schedule, others don't.
Keep in mind - between the time you heal and the time you get filled, you are probably going to be hungry and able to eat anything. It's called "bandster hell".
Don't do it! Stick to your docs orders on the amount and type of food you should be eating, regardless of how much you "can" eat at a time. I know, harder said than done. But avoid sugar and other high-glycemic index foods and it'll be easier. And even if you end up eating 6 oz of chicken at a time instead of the suggested 3 oz, that's still way better than snorking down a bag of potato chips and a pint of ice cream.
Good luck!! And congrats on getting banded, it's a whole new adventure.