This article suggests that this is a win-win situation for the startups and law students, but, it's a pretty one-sided deal here. This doesn't work out at all in the long term without unfair exploitation of the unpaid labor of the students.
While helping out gives the students experience, it's not reasonable to consider this any sort of real option beyond an occasional situation in which a startup can solicit a law-student who takes on a single case as part of their curriculum.
While helping out gives the students experience, it's not reasonable to consider this any sort of real option beyond an occasional situation in which a startup can solicit a law-student who takes on a single case as part of their curriculum.