I am with you U/H, very humourous watching some people come in the door and they think they are 'just' talking to 'the receptionist'. Alot of GA work places are tight knit. Make a tool of yourself at the front desk and good luck getting any further, no matter who you are speaking to.
Best just to be courteous, and yes, attempt to make an appointment or ask when the best time might be to catch the CP. If the CP doesn't want to see job applicants, you aren't in with much of a chance.