I'm not quite as sceptical as some about this. However, it's not clear to me how this differs from the sort of thing UNOSAT does all the time - here's their analysis of imagery over Abyei, the key border area between North and South Sudan. Actually it looks like the "Enough Project" is going to be using UNOSAT imagery itself, going by UNOSAT's own website.
If you follow the link you'll see that they have more than reasonable capability (50cm resolution) and that they routinely observe the presence of refugees/displaced persons and returnees, construction, and the like. There's obvious relevance to an effort to monitor potential conflict along the border, especially as oil prospecting is an issue. You can't easily hide oil exploration from a satellite that can resolve objects 50cm across.
However, the downside is that the UNOSAT report is comparing images over a two-year period. I would suspect that they will need much more frequent passes to be operationally responsive, which is where the costs get interesting.
Also, I've just been over to the website and it's a bit of an unstructured clickaround. What I've always liked about MySociety sites is that they all have a function - FixMyStreet reports things in your street that need fixing, WDTK issues Freedom of Information Act requests, TWFY looks up information on MPs, TheStraightChoice logged what candidates promised and said about each other during their campaigns. DemocracyClub, for example, worked because as soon as you logged in it gave you something to do and some feedback about doing it, and then it hassled you to do something more. It had structure.
Notoriously, if you don't give volunteers something to do as soon as they show up, they'll wander off. It is nowhere easier to wander off than on the Internet. And so there's a button to twitbookspace it and a donation link. There isn't, however, a to-do list or, say, a list of pairs of images that need comparing.