Inquiry: Your help on Swiss visa ruling needed! (Zurich)

Hi everyone in Switzerland!

I need your help: I work for one of Switzerland’s largest newsweeklies, «NZZ am Sonntag».

I’d much appreciate hints or help to find people affected by the following difficulties when applying for a Swiss visa:
For next Sunday’s edition I’m investigating in the field of visa-application for people outside of Schengen/EFTA who plan on visiting Switzerland (visa up to 90 days). Migration law’s been applied very restrictively in Switzerland compared to other Schengen-countries. I came across a case, where an EU-expat living in Switzerland (C Bewilligung) invited this girlfriend from Vietnam to Switzerland. He had travelled Vietnam for several month and fell in love with a Vietnamese woman. He wanted her to come here visiting him for a month in summer. She applied for a tourist visa handing in all required documents, including the invitation letter by her partner, resident in Switzerland. They had to declare their relation status and were asked to provide photos showing them together to proof the romantic relationship between them. Already that is beyond regular requirements for a tourist visa. That turned out to be not sufficient proof however: The authorities in Vietnam asked her to photocopy excerpts from their intimate daily conversation over Whatsapp-Chat. This clearly represents disproportionate methods according to lawyers familiar with migration law.

Have you encountered or heard of similar cases? Your help is much appreciated. Pls send me a personal message. My deadline for the inquiries is Friday night October, 5.

Thanks,
Laurina