Some people seem genuinely annoyed Vika isn't playing solely because it would make her more vulnerable if not this week, but in some later week. For top players though, scheduling is vitally important. Playing through injuries continually in February would be foolish. There is not a lot to gain from doing so. In the scheme of things Dubai isn't a big event. There's not a lot to gain, and a whole lot more to lose down the line.
And ha I'm not sure I would call that exho an official match
. I am not sure there will be a lot of effort going in from either side. I am never sure why they don't mix these exho's up more. You could create more fun scenario's, play a mixed doubles match, and mic the players up (like they did in Australian charity events). It's not like you're ever going to get Vika and Serena to play a proper match in them.