Yes, you suggest a way that may detect blocks. According to the researcher's website, he is using the search function of weibo to check which words are blocked, that is smart. It seems that weibo are using program and hiring people to do the censorship. There even are rumors saying that those censorship department are settled in WuHan city, and has a team of more than 500 people. Anyway, his research is valuable, and it helps bringing more sunshine to the weibo land.