They will never answer johnl. Here is the deal, and it took me a while to figure out. Boonex has been designed with an number of critical features not working. This one, in my opinion, is glaring. As you have correctly surmised, the way alerts are set up is absolutely critical to making a community work - but Boonex left out this absolutely critical function, along with a number of other. For each of these, you will have to buy a mod. I don't think this is fair - I think the base functionality of the software should work and it is almost a kind of bait and switch when you find that to make this software work properly, there are a bunch of mods you will have to buy.
I have looked at it, and I think to make D7 even have a prayer of working in the real world, you will have to buy about $500 worth of mods. No problem for some people, but funds are extremely tight for me - plus I have five sites, so I would have to spend at least $2,500 to make the software work properly. That is in addition to about 20 or so bugs and things that are incorrectly set up that Boonex never fixed, and you will find that far from being free, this software is actually quite expensive.