Holding up a blank piece of paper is a completely different scenario and topic! We are talking about normal, everyday travel for business and recreation. If you go there and do something taboo, something that's clearly intended to cause trouble, then what do you expect?

With any foreign country you should understand their cultural norms and laws. Your own ignorance is a valid consideration for travel, not being arrested as a political prisoner. You won't get in any trouble as a tourist or business person 99% of the time.