The whole situation with the vouchers is just weird imo. I first encountered it in May of 2021. Before then we'd always just walked up and had breakfast when we wanted (our trips are generally twice a year). On that trip we walked up and were told we needed a voucher to be seated. We asked the worker how to get a voucher and she didn't know. So she went and got a manager and we asked him and he said it was part of a vacation package. We politely explained we were passholders and couldn't book a package as we didn't need tickets and he shrugged his shoulders at us and didn't care. Restuarant was half empty but they absolutely refused to let us in.
Breakfast at Leaky Cauldron is one of our favorite things so we went to Customer Service at the front of the park to ask if there was any way to get a voucher and they told us the same thing as the manager, its part of a package with hotel and tickets. We weren't trying to get anything for free, we were perfectly happy to pay for a voucher, but they insisted it was only part of a package and couldn't be purchased separately.
We were only on a 2 day trip at the time so the next morning we walked up to the leaky cauldron and asked again if we could be seated just to see what would happen and they seated us right away with zero mention of a voucher, didn't even ask us if we had one. It was a different worker at the door that day than the day before. The whole fiasco was just very odd.
After that trip I found out from someone on these boards that you can purchase the vouchers separately by going to the vacation planning desk in an on-site hotel. Next time we went down we were at RPR, went to the vacation desk after dropping our luggage off and they were able to book us vouchers for 2 days of our trip. They never asked if we were staying at the hotel, I think we could have walked in off the street and paid for the vouchers without being guests. Both times we went to have breakfast we were asked if we had vouchers before being seated. I did not ask if we would have been seated without vouchers so I'm not sure. If you really want breakfast there, like we did, I wouldn't risk it!
I will add that being turned away that one trip and having all the staff be so uncaring and so unhelpful was very upsetting at the time and I think the voucher system is just stupid, mainly because it isn't advertised for people to know ahead of time unless you have a good travel agent or are on boards like these and I can't imagine that this system isn't costing them money from turning away customers from food they want to purchase. And every time Universal sends me a survey in my email I fill it out and I tell them their voucher system is stupid.
Okay, rant over lol