Is it ever tempting to make a deal with a 'frequent flyer' that you won't tell them off for calling an ambulance they don't need as long as they've put the kettle on before phoning? Or perhaps on a more serious level, get a proper teapot and a tea cosy for it to have at the station. Stays within the drinkable-temperature-range for ages, that does, and everyone can pour a cup, swig it, and top up the tealeaves/water as needed within a two-minute window.