ATC perspective:This particular KSAN DP actually calls for a hdg to be flown. If taking off from Rwy 9, you should manually turn left hdg 290 to intercept the MZB 314R, then track outbound to BOKNE... Rwy 29, ATC would expect you to turn right hdg 297 to intercept the OCN 155R, then track inbound to BOKNE... In some cases depending on the existing traffic situation, ATC will issue a hdg different than what the DP calls for.Hope this answers your question.Ken