The best solution is to not mandate them IMO. If you create strong incentives for fraud with something that’s difficult to authenticate then you shouldn’t be surprised when it happens a lot.
It's hard to "crack down" on something that you could basically print at home and fill out yourself. That is unless something is developed to link the vaccination to your identity record. I've heard that there is work going on to associate a unique UPC code do each dose and then you could scan/attach it to a data record that could be verified either on your phone or in the cloud.
From the way all of the current vaccine passports "work", I would guess not.<p>Who could have thought that the government trying to roll out an app/service to millions of users overnight would be flawed? /s