Note that sometimes there is a cover charge of HK$50 to HK$200 at clubs, which may or may not include a couple of drinks.
Sometimes there is a cover charge at clubs, but only for gullible tourists. 
mnli hypothesis: Sometimes there is a cover charge at clubs, but only for gullible tourists.  premise: Note that sometimes there is a cover charge of HK$50 to HK$200 at clubs, which may or may not include a couple of drinks.