Sounds an interesting idea.
In particular the tracker initiating a mountain rescue call out seems great on paper - however what is the failure rate of these trackers? When we did the south wales traverse last year using a tracker there were several hours where it didn't update as it required mobile phone reception (and one of these areas was the area of your race route)... How tough are these trackers, Is there a temp limit or water resistance and have these things been tested? If not there could be risk of a false MR call out (indeed, much better to a late, but needed call out)
Are there going to be any entry limitations?
Are these 'gadgets' going to increase the cost? Although I'd have thought that the increased simplicity should outweigh the costs at your end for sure (for example, Long Mynd Valleys Race needed 57 marshal's for the RO to feel the needs stipulated by new FRA rules covered...)
So it sounds an interesting plan to me, and I hope it works, and if it adds a new and testing AL to south wales, then great!
A Borrowdale of the south? Does that mean Dave is going to beat you again Ed?