I agree with this. Its kind of pointless to have a reservation system and not be notified if someone reserves something and I certainly don't have the time to manually check it continuously. This is a feature that would add great value but is not used due to this limitation.
I did a end user feedback session with Solarwinds WHD team members about a year ago and brought up this exact issue. We were looking to use it for corporate cell phones with international plans that can be signed out if you are traveling for the college and leaving the US. Unfortunately there currently is no way to get an email, have a reservation create a ticket, or link a ticket and reservation the fact that none of those options exist really limits the usability of the reservation feature. At a minimum you should be able to have am action rule that can create a email to a tech or tech group.
Likewise, we never got a working solution for this within Webhelpdesk.
We eventually put reservable assets into Outlook, so phones / laptops can be booked like a meeting room. Email rules can then be set to create alerts.