The problem is installing the app, that's the part I don't want. All you said applies to the case in which the app is installed.

Edit: just to elaborate a bit further in case it's not clear: should people who don't have a smartphone, or their smartphone is broken, or maybe they forgot the charger home, still be allowed to park their vehicle in a public area? Isn't there a higher standard in terms of accessibility requirements, when you are providing a public service?