Some friends of mine are going on a cruise next week and one of the ports of call is Djibouti. Yemen was also on the schedule but that has been cancelled since the bomb scares from that region. I understand that Djibouti is quite a common port for cruise ships and I find that puzzling to say the least.
Cruise ships bring people with dollars to spend while visiting (however short the visit). Common sense decrees don't mess with a regular income. Most likely it's safer from the ships operator perspective to schedule a visit which, in effect, will most likely grant some sort of 'protection' than chugging past the place. Just musing on my part.