[Symbiote]

Metro ticket machines in Beijing won't sell a ticket until you've scanned an identity card.

Tourists must wait at the ticket window. Foreigners aren't usually asked to show the passport unless they look Chinese.

[dom3k]

No need to wait at no window. After you activate Alipay, just click on "Transport" and create a metro card for Beijing. Scan code on enter, scan on exit, pay the sweet low fare automatically. One app, 30+ cities.

[Symbiote]

"Activating Alipay" requires using an identity card or passport.

[dom3k]

You don't have to wait at the ticket window though. Privacy? Maybe not. But convenience? At every corner.