General Engineering Introduction/Justification
Some projects must be justified for two reasons: it is unclear who the customer is or there is good evidence the customer may not change their lives to accept the fruit of the project. "Not yet illegal" projects have to approached from a very positive, well justified starting point.
For example, most student automobile related projects are hard to justify. Putting a DVD player in the dash board for one's father is not justification. The customer can not be a family member. This is a conflict of interest. The goal of an engineering project is to improve society or change the world; not benefit one's immediate family.
However an automobile project that tries to extend or change the information presented on the dashboard is a good project. A project that hacks the wireless communication in the car, that manages ECU configuration or the parses the OBD information is more easily justified.
Another example are airsoft or paintball projects. These are team sports that involve maintaining an arsenal of equipment. It is no different from any other support. And it has already evolved into robots shooting each other. The problem is that it is hard for a school to justify a project that requires engineers to work on guns .. even non-lethal guns. Insurance and political problems require very thorough justification. Justification can take a lot of time, require interviewing lots of people, taking surveys to prove need and creating long documents.
The justification need grows naturally out of a project. The exact nature of the justification can be very different from one project to the next.