I think it's a little more nuanced than the wikipedia article suggests, I saw some other sources saying that they're allowed to hand out stuff, but not if it's like a reward for signing up for the card. For example: handing out a shirt in exchange for applying wouldn't be allowed, but handing out a shirt to anyone that visited the booth would be ok.
(2) INDUCEMENTS PROHIBITED. —No card issuer or creditor may offer to a student at an institution of higher education any tangible item to induce such student to apply for or participate in an open end consumer credit plan offered by such card issuer or creditor, if such offer is made
from https://www.ftc.gov/sites/default/files/documents/statutes/c...:
(2) INDUCEMENTS PROHIBITED. —No card issuer or creditor may offer to a student at an institution of higher education any tangible item to induce such student to apply for or participate in an open end consumer credit plan offered by such card issuer or creditor, if such offer is made