While some events are pretty laid back, it looks like the registration for this event cost ~$2000, which is a pretty penny. My gut instinct would be to check with the event organizers first before trying to bring a +1, but I think the OP assumed that because he was able to negotiate with the travel coordinators for two one way tickets, one for his wife (instead of one round trip ticket), he probably assumed that this was implicit consent for his wife to tag along at the conference. Seems like a big mis-understanding that was confounded by poor treatment from security staff (and before we start ragging on the security staff, it is worth mentioning that event security tends to be a thankless, miserable job. Crappy wages and hours, and depending on the event, you spend most of your time dealing with people who treat you like shit.)