This is a video of a fine diner doing a little experiment to see how much bigger a 'large' weizen style glass of beer is at Applebee's than a 'small' pint-style glass. At first glance it would appear to only be about two ounces. Although it looks like she starts with a beer with zero head and some empty space at the top so the glass is probably already missing two plus ounces, and there are about two left over after she fills the smaller glass to the tippy-top. So I'd estimate there's actually about a 4 - 6 ounce total difference between the two glasses. Of course you could just ask a waiter what size glasses they are. Or constantly ask to speak with a manager because you're convinced the bartender is chronically underpouring your white zinfandel and welcome to dining out with my aunt! She also always tries to order from the kid's menu and tip with coupons to other restaurants.
Keep going for the video while I try to remember the last time I even went to an Applebee's for happy hour without getting arrested. Also if anybody knows what the cost difference is for the beers feel free to chime in with a cost analysis.
Thanks to JD, who agrees this is exactly why you bring your own beer and chug it in the restroom like a normal person.