I live within 1.5 miles of Class C KCOS. When I fly as a hobbyist I telephone both the Tower and KCOS OPs Ctr.
Then I can compete with the hot air balloons, aeroclubs, geese, and occasional FFL. Always I yield! (Aeroclubs are usually 200-300 due to the close proximity of the small ac landing pattern. Absolutely no problems or denials yet. I also fly elsewhere in the city which requires the heliport/hospital notifications, >90% of the time, no answer!. Butts field to the south is hit or miss. Air Force Academy to the north? Rarely, that area is sooo busywith parachutes, gliders, aeroclub, small rocket (5-10 foot) lessons for Academy students. East of The Springs in the wide open areas, military jet jockey training from much further away places.