Two things. First, I can't comment on whether the towbarless tug is new for the 737, but it certainly isn't new to GSX. Second, if you go into the GSX settings, under timings, you'll see a setting that reads "Inverval between "Waiting for your action" messages." By default, it's 10 seconds. You can increase that to 60 seconds or so, so you don't have to keep listening to the "release parking brakes."