Two things to remember here regarding reserve members.
Most of us are either students, or employed, or in my case, both. 5 courses in university, plus I drive a big rig truck as a part time job. I need my weekend money to pay rent and food and bills. Leaving on an FTX on a voluntary basis with cadets means dropping 25% of my monthly income. That is a lot of money when you're on a tight budget. And if I take time off, like right now, it's to spend in books cramming like a madman for finals.
Now I'm an extreme case. Not everyone is that strung out with time and money. Would I be done with school and have free weekends, I'd do it on a voluntary basis. It looks just as good in a resume as volunteering with the Big Brothers
Here's another issue. The regiment pays for the member. The regiment is also on a tight budget. So for the pay problem, the regiment might just not want to waste the little work days they have for actual training on such a project. Of course there's always ways around this, like splitting wages between the regiment and the corps and whatnot.
As for asking for volunteers, I've never heard such a call.
Personnaly, I'm all for a kind of a program like this and I like the idea. And I think I might toss it around with some people at the regiment.