They were along with others, valid scenarios. But they were not the point being made
They were bonkers. No-one (well maybe a pitbull-owner) would pay for a fake Animal Health Certificate at £100 - £300 or probably more. (what's the price of a fake MOT theses days?)
When a genuine Pet Passport that lasts the life of the pet is available for £60.
I have been fortunate, Brexit has enabled business opportunities and significant personal savings.
And you have fully converted to Brexit since?
I agree, though the risk for a UK pet going to the EU and back for a couple of months is likely to be extremely low.
Or non-existent, in your scenario of the pet staying there while,the owner is obliged to leave.
The risk of illegally imported dogs is far higher to the UK. Something that the UK vet industry noted.
Aren't you getting yourself mixed up now?
One minute you're talking about Pets passports and Animal Health Certificates, i.e. legal entry into EU and UK. Now you're discussing smuggling of animals into UK, none of which would require a Pet PAssport, nor an Animal health certificate.

Talk about hop, skipping and jumping around, are you an olympic champion? You move like one.
Rabies is a nasty way to go - animal or human.
Any recent UK infections were contracted while the person was abroad.
The 5 deaths that have occured in Europe have been rabies contracted from Bats.
So I think your concerns are OTT.
The vigilance continues. But that is irrelevant to Pet Passports or Animal Health Certificates.