Tap in a Flash, but who will pay the bills?

Advertisement for Interac Flash, SkyTrain station, Vancouver, BC

Interac has entered the wireless age. Tap payment has been a feature of credit cards for a few years. Interac, the organization that manage the debit payment system in Canada, has begun an aggressive campaign to publicize its proximity payment system, Flash.

The main selling point seems to be the "Zero customer liability". The whole system is explained in an infographic on the organization's website.

(Source: http://www.interac.ca/images/Interac_infographic_ENG_FINAL_2.JPG)

All of the communication from Interac stresses the fact that there is "Zero customer liability". So who is taking the risk? Is it the retailers who accept Interac Flash? I've written to Interac to find out. I wonder if I'll get a response?