I disagree with this move. Why should we force a cap rather than let market competition improve prices? I believe it's better to fix shady practices. If I pay 25% to Uber, I want to know I paid 25% to them and not the restaurant. Then I can decide if the time savings is worth that 25% or not.
That's true of any company/workers/suppliers. People only know and care about how much they end up paying. As long as there's a minimum wage, people don't know, and usually don't care how much a company pays their workers/suppliers.