Is This Even Legal ? - 49ers' Levi's Stadium to go completely cashless when fans return

I question whether this is legal as US physical currency is Legal Tender.

It's one thing to offer the option of cashless payments while at the same time taking physical currency. However, to bar payments by cash entirely at an in person event seems like it could result in legal challenges to me.


49ers' Levi's Stadium to go completely cashless when fans return
[link to www.foxbusiness.com (secure)]

Excerpts -

Fans who only have cash can opt to put it onto prepaid card worth up to $500

Visa, which is a major 49ers partner, will offer fans who only have cash the option of putting it onto a prepaid card worth up to $100 with no transaction fees, according to Sports Business.

The Kansas City Chiefs, Jacksonville Jaguars and Atlanta Falcons have already offered cashless payments.