Why not, if there are creeps on a map that give resources?
Well, you have to work for those and invest some time/resources yourself to be able to kill said creeps.
Now, on the idea of random bonuses as a whole, I think it could be very interesting to have a designated part of the map, such as a circular summoning platform in the middle that randomly spawns a bundle of a rare resource (with a fair warning ahead of time, so players can react) every so often.
It's equally random for both players, except in the case where one player has far more map control than another. But even then, it doesn't really give any advantage that having fixed resource nodes at that spot wouldn't. Instead, this is just a spot you need to hold momentarily until one of your workers can grab the bundle, and then you can GTFO, rather than build a highly vulnerable resource gathering structure there.
I think it would spice up the metagame a bit. Imagine having multiple "summoning platforms" at strategic locations. The battlefield will constantly shift based on which platforms are currently "summoning" in resources. In fact, it could become its own gamemode if you severely limit the traditional resources available on that map.
A good analogy for Supcom players would be to say that at random times (eg, 5 min, 10 min, and 17 min) a destroyer wreck is spawned on, say, the raised hill in the upper left corner of Theta Passage with one-minute's warning. Or the land-bridge in the middle of Setons. Or... (I think you get my point).