I've been seeing references to this type of thing for years and years. It's nonsense. It's a misunderstanding of how audience selection works. They actively try to achieve "balance" when you apply to be in the audience. I've been in the audience, when it was in Glasgow many years ago. A researcher called me back and asked me about my politics. He asked me which party I thought I was closest to. I said none, I was an anarchist. He said "we've not got any anarchists yet. Are you an SSP supporter?" I said "Absolutely not".
There was a list of profiling questions, while they tried to work out if I was going to skew their audience. That's how it's done. So of course there will be Tory activists in the audience. And Labour. And Lib Dem. And, if an SNP panel member is present, SNP. And so on.