Manthink;corruption/scam/cheaters/con-men are part & parcel of any free economy...not just in "Communist" China.
I'll take odds on mainland Chinese being the worst in the world, for ethics and poisoning their own people out of greed on a large scale, government officials and guanxi relationships all included.
Having lived in Beijing in the early 90's, and having a number of guanxi connections, and family relations from pre 1949 days, not to mention the World Bank and the business rsik factor, along with all the events of Taiwanese businessmen being ripped off too...I would say caution is the word wouldn't you! Guanxi being a fundamental starting point proves nothing until experience proves otherwise.
In China the westerner and others have always been fair game at the expense of the Chinese ethical behaviour, in which it will take generations to repair. Of course corruption happens the world over, it can and is measured statistically, and like the old saying goes, high the risk, high the returns, legally speaking too.
That isn't to say one shouldn't invest in China, you just have to be well prepared and understand the cultural differences, guanxi is not always a good thing but it helps in most circumstances, and my own friendships within the Chinese community put friendship well above the $....Which I find would discourage even many western relatives.
Meaning that my guanxi friendships are quite reliable up to an unknown point. After that who knows, the weather blows in different directions.
In terms of investing in Countries one needs to weigh up the pro's and cons, the risk factors determine the way. Then you decide if and when you can afford to lose
The Chinese are still learning the difference between short term greed and long term investment, honesty and trustworthiness rules no matter what creed or colour, though much damage is very apparent in mainland China for small investors getting robbed of their investments. Only large MNC have the financial backing to follow through with counter claims, guanxi and paybacks.
I've even seen mainland Chinese cheating their own generous relatives in the Republic of China, through corrupt practises, now that is sad and quite appalling that greed can be so evil.
The legal structure leaves much to be desired, and it's the same in many emerging markets, SE has probably first hand experience of that too in his line of business. Risk assesment is always being updated!