When the Iron Triangle becomes an Iron Rectangle

We usually speak of the Iron Triangle (aka Time, Resources, Features)
when it comes to software projects. More often than not this triangle
turns into a rectangle when you are working as a freelance consultant.
The people are not only hiring you to produce a certain amount of
features within a given time frame while using a certain amount of
resources, they expect you to train their internal staff on the way.
This can take some work and it will result in less features, or more
time or resources used.
In the past I often forgot to point that out to the people who are
hiring me. Thankfully my new assignment is mostly about knowledge
transfer, even if we will be developing useful software on the way.