Security isn’t good enough yet to go cashless. Until it is you have just as many problems.
There’s no reason to have fees. I feel it’s bad business and refuse to charge my customers a fee. I view the fees I pay (as a business to CC company’s) as just another cost and it’s ultimately in my price. There is no discount for cash and no fee to use either cash or CC’s.
Discounts for cash are so companies can tax evade and I find that practice dishonest and do not frequent those establishments or give my business to those who do that sort of thing.