While of course a fancy formal event is always fun for those of us watching, I'm not entirely sure it's in the spirit of this trip which is very much about empowering women, engaging with people at a grassroots level and shining a light on issues like poverty and inequality. Also in light of the fact that there do seem to be a LOT of day time events, I can't say I feel that they are doing a shoddy job if they choose not to work in the evenings too. I mean, this trip is probably going to be fantastic but being "on" constantly, with cameras and people watching constantly can't be easy and if I'd done that all day I'd want to chill ou tin the evening and hang ou twitch my baby too.
Also, for record, in South Africa super fancy formal events aren't as big a deal. I was quite surprised when I moved here and found, in my 20s, that people were always going off to formal balls and other events as fund raisers or for parties etc Our equivalents tend (not always, but overall) to be more casual, often more family orientated etc. You might do a formal evening for a big birthday celebration or something, but it certainly wasn't the same.
eg when I worked in the City in London I went to at least a couple of black tie events a year. In equivalent roles in South Africa when I worked there I don't think I went to a single black tie event. Semi formal/ work wear events in the evening, sure or other events. But not full dress up.