Whilst it's very easy to say that we need Waymarkers in pairs, and half a dozen TECs and so forth, I think that often Simon has to hunt around a bit to find people to do these roles (as he mentioned briefly earlier in the thread), and understandably doesn't like to ask the same people repeatedly.
It does vary from ride to ride, but some rides can be particularly thin on people who are well known to Simon, which can make it difficult. I seem to recall that the Genteel Ride tends to suffer from this, because the Dun Run is the next day, and most people balk at doing two night rides in quick succession (I know I do!), and quite a lot of the more confident regulars who will likely make up a fair chunk of the TECs and waymarkers. I'm sure other rides probably suffer a similar problem from time to time, and indeed this ride was probably a bit thinner than usual, since I can think of a handful of the more regular attendees who weren't present.
A few other thoughts come to mind:
(i) Sometimes the TECs (and accompanied "back of ride" riders) will come across a fairy visitation or other mechanical, part way through being dealt with, often by one of the other regulars who isn't actually acting as a TEC (I've done this myself a few times). There tends to be the assumption then, that they've already called through to Simon that they're dealing with a problem, but that may well not be the case.
(ii) Possibly we need to make sure that someone at the back (ie one of the TECs) is clearly the "official" All-Upper (head TEC?), so there's no ambiguity about who says it, and whose responsibility it is.
(iii) I normally carry a moderate amount of tools and spares on group rides. It may be useful if we know what is being carried, or possibly let Simon knows, so if someone has need of a certain class of tool or spare, then we (or Simon) knows to call for it, or send someone back if necessary.
I know I carry more kit than most (!), and even when I'm cycling Red, aside from the predictable inner tubes, tyre levers and pump I'll also carry: CO[sub]2[/sub] cartridges and inflater, a multi-tool, a Leatherman, a couple of the more common full length Allen keys, a brake cable, a gear cable, an emergency Kevlar spoke, a boot, a spare set of lights (and batteries to suit), some AA batteries, a puncture repair kit (for when you run out of tyres or have an unusual tyre size to deal with), a few random spare nuts and bolts, a selection of cable ties, a Spokey, and a VAR lever for those tyres which really don't want to go back on.
When I've got a pannier, I'll normally also carry a complete set of Allen keys, a few adjustable spanners, some cone spanners, a small pot of oil, some disposable gloves, hand cleaner, more inner tubes, and a spare tyre (700×25 or ×28 as a compromise size to fit most rims).
On occasions people have had problems that some of that could have solved, but didn't know that I had the kit, and I wasn't TECing, so I wasn't at the back in a position to know that I could have helped.