Those are convention tickets. I don't know if you can use them w/o having to prove which convention you're part of.
I have e-mailed them to clarify and will advise once I get a reply. Here are the details of the ticket and I do not see anywhere it states that they are for convention participants only unless I missed something.
1-Day Base Ticket Plus CityWalk® Party Pass
(Valid after 2:00 PM)
This pass entitles the guest admission to EITHER Universal Studios® OR Universal's Islands of Adventure® after 2:00PM for one (1) calendar day, plus admission to select live entertainment venues at Universals CityWalk entertainment complex..
The Wizarding World of Harry PotterTM is at Universal's Islands of Adventure®.
RESTRICTIONS:
* The above Admission Media is non-refundable, non-transferable, and must be used by the same person on all days.
* Limit ten (10) total admission tickets per transaction.
* Valid only during normal operating hours.
* Parks, attractions, or entertainment may: close due to refurbishing, capacity, weather or special events; change operating hours; and otherwise change or be discontinued without notice and without liability to the owners of Universal Orlando® Resort.
* The above Admission Media specifically excludes admission to separately ticketed events at either of the Universal theme parks or within any of the CityWalk venues. Some CityWalk venues require ages 21 or older for admission.
* This is an exclusive online offer and is not available at the front gate.
* Print@Home tickets are only valid for the person listed on it (you will be asked to enter each ticket holder's name).
* Print@Home tickets and non-Print@Home tickets cannot be combined in the same ticket order. Please group all Print@Home tickets into their own transaction / order.
* Valid Photo ID required.
* Does not include admission to AMC Universal Cineplex 20 or the Blue Man Group Show.
* Additional restrictions may apply and benefits are subject to change without notice.
* Unless otherwise stated, parking is not included and there are no discounts on food or merchandise. Valid Photo ID required.