They do not pay their interns, but expect part-time (15+ a week) or full-time (40+ a week) commitment. This is exploitative and taking advantage of people, and I recommend that if you are given a job offer to demand payment because they pay a senior intern who does the exact same work as you (with some exceptions). I believe this is most likely illegal as well to have several interns doing the same lab work, taking their data and then only paying one. Either demand payment or do not work here. It comes to the point that you will be making a negative net amount with the cost of travel and other living expenses. Exploitation of labor and reliance on the legal ignorance of their young interns is cruel. You deserve to be compensated for your labor; it is your right.
Advice
Either demand payment or do not work here. In general, unpaid internships do not end up beneficial to students.
This review is based on my experience, and it is not unfair or false in any way. What is unfair is uncompensated labor and what is false is trying to spin unpaid labor as a benefit during a global pandemic. Do not let an employer try to silence you or intimidate you. As a fellow worker and student, I am not lying to you. Go with your gut feeling telling you that an unpaid internship isn't worth it.
Remember: you deserve to be compensated for your labor; it is your right.