You may recall that Public Order Act in the form it is today was one of the products of the IPPG reforms of 1997 which came about as Moi ceded some ground after a lot of agitation by opposition and civil society organizations.
True, the law says the convenor will notify the OCS. There are situations that may make the OCS advice against the meet or procession being held where and when proposed. However, political twisters will make it look like it is denial of permission so that they play victim.
Edit: I have deliberately avoided the RAO question because I do not have enough information about what he was doing yesterday.