Normally, a good B&D scene creates a certain mood and ambiance in order to heighten the experience for both "master" and "slave". And while it is important to be concerned for the slave's comfort and safety, showing too much consideration can make a master seem less dominant to the slave. And since Alice is always putting in her "two cents," that may be the reason why she ends up wearing bigger and tighter gags for longer periods during their B&D sessions. Hey, I'm just saying! (Medium: pen and ink).