So we sent our best drinker of free drinks (me) to investigate. Here's what was discovered.
The restaurant was mostly empty when I arrived on a Tuesday afternoon. The staff escorted me to a table and handed me a menu that I did not look at. I ordered the free Sangria. They politely asked if I wanted any food with that. I said no. They brought me the Sangria. The end.
I know what you're thinking. It was some junk liquid made with fake alcohol powder and tap water, or just the tap water. Or at best, it's that low level crap you find at a shoddy ladies' night in some terrible club.
Nope. Not at all, my dear Shanghai-trained cynics. This was a real drink made with red wine, fresh fruit, sprite, and rum (which you'll notice when you get to the end of your drink and really, really notice after your third glass).
Despite the fact that there was no judgement from the staff -- no "hey you should order something else you lousy, cheap bastard" -- I made it through my second round before giving into the shame and ordering something off the menu. Your results will vary, depending on the thickness of your skin.
The deal supposedly lasts through the summer, but you might want to call ahead to confirm when you go because this is the type of promotion that might get out of hand and be shut down immediately. They also have a nice patio area in front of the restaurant. Drink up.