don´t get too astonished - and also don´t be afraid - when you want to enter a shopping mall and a security guy asks you to open your bag or be checked with a metal detector. It usually means the terror alerts are higher again. most of the time, it is just routine, for the safety of all. Being so close to a fragile place like Somalia, and receiving threats from radical groups like al-shabaab militia means an attack COULD happen. with borders difficult to control especially in the vast north or along the coast, it is better trying to be safe than sorry. There are also security checks at a number of hotels, even if there is no international conference with some high ranking politicians going on. it should not spoil your holiday - fact is, Kenya is not exactly in the most stable region of the world, but there is no need to get overly nervous about this either.
Some people are completely confused about the Matatu system. You don't have to be if you know what to do:
When looking for a Cab torwards Community or the direction of Uhuru Park, you want to be Next to KCB on Moi Ave. If you cross over to the Hornbill, you can pick up buses and matatus headed into town, Buruburu and outskirts. If your still confused, look for the posted route.
Snapping your fingers in the air is the common method of getting a Matatu driver's attention. To exit, simply say " Hapo" meaning "here" or wrap on the side or top of the \Matatu loudly 2 times. Buses have a buzzer button like in the US or UK that you push to signal a stop.
If a fare collector shakes his palm up and down when he approaches you, he's essentially asking if you are going to get in or not. A nod means that you indeed intend to board.