Looking for this feature myself, I think I'm just overlooking it. This feature must be there, because I can't believe such a simple feature isn't implemented right now. (simple as this: if report X has >0 items, mail it one time)
In case this is not implemented yet: this will make LS a (nearly) full-fledged monitoring Software (using PRTG for this right now). Although LS will not have graphs/history for Data, alerts would still be sufficient for SOHO sites.
By the way, sending "alerts for reports listed in the web console's Reports tab, which are sent on a scheduled basis" as described here: http://www.lansweeper.com/kb/113/sending-email-alerts.html are not alerts. It's not an ALERT if you send it on a scheduled basis... It's, well, it's sending a report on a scheduled basis!
Alerts happen just in time, simple as that.
Who the heck came up with this misleading clarification?