As we say in translation: It all depends on the context.
Most certainly, a student taking on a translation or interpreting assignment will do so, among other things, with the intention of gaining experience and making himself/herself known to potential clients. For this reason, if the student is mentored by a professional, it could represent a great opportunity for all parties.
However, if the intention of hiring a novice interpreter/translator is only to cut costs, this reflects a lack of commitment to the audience and to the international speaker on the part of the organizers and the result can be disastrous.
How much do you save with a non-professional?
A young professional or advanced student should not charge less than 70% of the rate of a professional. However, remember that in the simultaneous interpreting booth it is always advisable that at least one of the interpreters has sufficient experience. The first time we face the booth, we have to face the audience in front of us and that can be intimidating. Not to mention the skills, the "savoir-faire", the experience that helps you to react rapidly and that allows you to run an interpreting booth. Being bilingual is not enough to interpret or translate, it is certainly a fundamental ingredient, but it also requires study, technical knowledge, practice and ethics, among other things.
If you get someone to provide the service for less, the quality standard of their work or their ethics is at least dubious. They may not be up to what you need and in this case I ask: would you seek the services of a butcher for a surgery? Is it worth risking the success of an event after all the investment involved (logistics, food, transfers, fees, decoration, equipment, staff, experts, etc.)? I may even say that without ensuring the effective delivery of the message, the potential for disaster is extremely high. A professional translator / interpreter is precisely the one in charge of ensuring that multilingual communication really overcomes language, cultural and technical barriers so that the message gets to your audience with sucess and as intended.