While random sampling stands as a valid statistical method in polling, directly applying it to a concert audience context oversimplifies the situation, considering various influential variables.
For instance, fan demographics play an important role. A video might not precisely portray the diversity of concertgoers. The substantial presence of Chinese fans doesn't necessarily diminish local support, it could be influenced by factors like travel trends, global popularity, or even the timing of the concert.
Moreover, concert attendance doesn't always reflect a group's overall fanbase. Variables such as the concert's location and the nature of the event significantly shape the audience composition.
Kpop idols face restrictions on having concerts in China, prompting Chinese fans to travel to South Korea. The global popularity of a group attracts international fans, especially from neighboring countries. These factors influence the overall demographics of concertgoers, making it an exception rather than the rule. Hence, these concert attendees may not accurately represent the group's entire fanbase in Korea.
To point out your flawed logic using random samples.
A random sample makes sense under conditions where the goal is to obtain a representative subset of a population (in this case how much local fans they have), ensuring that each member has an equal chance of being included. This method is appropriate for situations where the characteristics of the sample need to mirror those of the entire population accurately.
In the context of a concert audience, using a random sample might not be suitable due to several factors. Concert attendees are not typically chosen randomly, instead, they self-select based on their interest in the artist or event. Moreover, the demographic composition of concertgoers can be influenced by factors I already mentioned above. A random sample may not capture the nuances and specificities of the concert audience.
To make it short, this doesn’t prove that they lack the support of local fans, not even scientifically!