the answer is you don't. for whatever reason (and she may have valid ones), this is her behavior and you can't control it. you can control yours, however. for instance, if you are done eating at the restaurant as stated above, there is no need for you to stay for a 30 minute feeding session...just say it was great getting together, looking forward to the next outing, then go.
for example 3, um, wow, that is some level of comfort she has! In that case, why not head off to a slide or lazy river or something.
the thing is, you are uncomfortable and she is not. you can both meet your needs...just remove yourself from the situations that make you uncomfortable.
for what its worth, I did bf in public but didn't go on display...only one breast at a time, and the baby or my shirt pretty much covered the situation. my kids HATED blankets/burp clothes over them, so that didn't happen in my world. still, it was not easy (unless you were looking) to see even an inch of breast, and certainly you never saw more than people see at the beach or on network tv.