Absolutely it is a bad idea.

Just say they would like to have a trip in US. It will be very helpful if you can provide a letter that includes a detailed and reasonable trip plan for your parents such as New York ten days, Califorina 15 days or something like these. I guess the more important things for them is what is their strong relationship with China. For example, their other kids in China, their income,job, deposit in bank and even stock if they have. Just try again and they will be fine.