Everything you can grab from a silent push in those months when you don't check in but still have the app installed out of convenience. In other words: not much, but something (e.g. the company can know that the app is still installed).
I wouldn't go to lengths avoiding installation (just remember to uninstall if it really bothers you), but I'd prefer a purely web based implementation. How about clearing arbitrary NFC UID for access? (From a self-serve counter if taking humans out of the equation is so much of a goal) The credit card form factor is certainly not inconvenient at all, but dealing with them can still be surprisingly annoying when that happens to coincide with oddities from the very long tail of luggage situations.
I wouldn't go to lengths avoiding installation (just remember to uninstall if it really bothers you), but I'd prefer a purely web based implementation. How about clearing arbitrary NFC UID for access? (From a self-serve counter if taking humans out of the equation is so much of a goal) The credit card form factor is certainly not inconvenient at all, but dealing with them can still be surprisingly annoying when that happens to coincide with oddities from the very long tail of luggage situations.