Yes it is possible for public view i.e., an user with ThingWorx View app can scan the ThingMark and view the associated Experience.
public means that you dont need user/password to access the experience.
You can set it up from directly your experience in Studio: "Info / public".
However you will not need to enter an URL into thingworx view app, if you use the thingmarks that were provided with your Trial/ bought edition.
Those Thingmarks are automatically linked to your experience server.
However the behavior could be different if your mobile device is hooked to a proxy forbidding to access our indexing service.
Did you try it when being on a mobile network (without any proxy / company vpn).