Since developing upon the Metaphors of Business work, I've noticed two different metaphors that are commonly used for such validation processes; Checkpoints, and Gates. Let's have a closer look at these metaphor.
The metaphor of checkpoint reminds me of a car race. The driver is going around the course and it's time to go into the checkpoint. They pull into the checkpoint and stop. The people at the checkpoint rush around the car and check that everything is okay. They are assistants whose intention is to check everything as quickly as possible, then get the driver on their way. The driver is relatively inactive in the process.
The metaphor of gates reminds me of an old fairy tale. The hero is on his journey and arrives at a gate which is guarded by a gatekeeper. The hero has to approach the gatekeeper and satisfy them in some way such as answering questions or giving them something. The gatekeeper is interested in nothing else apart from his prize, if the hero doesn't give him the prize then he doesn't get through the gate. The hero has to work to prove themselves to the gatekeeper in order to get past.
Relating these metaphor back to project validation points made me realise that the metaphor translated relatively well in most instances. Thinking back to workplaces who used the checkpoint metaphor, it was a less active process and the intention was for those taking part in the validation to get through it quickly and get things moving as easily as possible. And for those workplaces who used the gate metaphor, those doing the validation were much more like gatekeepers whose intention was to stop the project until such a point that they were satisfied their criteria were met. Of course there were exceptions, but these generally did fit.
So when is each appropriate? With situations which lend to the use of relatively self regulating projects teams, and where there is a fairly low level of external criteria to meet, checkpoints tend to fit better. With situations where many external criteria are crucial to be met, and with with less self regulation within the project team, gates tend to fit better.