System and methods are disclosed for interactions with unattended retail machines (“URMs”) using detectable trigger conditions and limited-scope authorization grants. An exemplary method is performed at a mobile device and includes: receiving, via a communications unit, a broadcasted signal from an electronic payment device coupled with an URM. The broadcasted signal includes a request to authorize funds that are associated with a user of the mobile device for use at the URM. The method further includes: (i) sending the request to a server via the communications unit, (ii) receiving, from the server, an authorization grant (e.g., the grant expires if predetermined criteria are satisfied), and (iii) detecting a trigger condition to initiate a cashless transaction with the URM. In accordance with a determination that the predetermined criteria haven't been satisfied, the method includes: initiating the cashless transaction with the URM by sending the authorization grant to the electronic payment device.