According to rumors President Trump suggested all protesters against him to pass a drug-test and announce the results. Mr. Trump has said his advisors that too many of Hollywood stars and liberal NGO activists are protesting and "as everyone knows", most of them are regularly using drugs. It is not moral such people to influence the public opinion by hiding their real nature.
"I will advise all protesters against me to pass a drug test" - these were the words of Mr. Trump to his advisors on a special meeting at White House. It was held after at airports protests started in support of foreigners that were stopped from entering USA, due to the new executive order against Muslims and Arabs from a list of too risky countries.
Part of Trump team opposed the idea saying that The President does not need this direct attack on liberal and Hollywood snowbirds. Media and other sources will ask this question anyway in the future. The prestige of Hollywood is not guaranteed positive so much people will start asking questions. So Mr. Trump decided to postpone this public comment, which does not exclude it to suddenly appear in any of his tweets...
Some years ago Italian journalists have secretly taken drug samples from part of members of Parliament. It was done with inviting them for participation in TV show and while preparing them in the makeup room before the interview. The result was that 16 of 50 tested deputies were positive. The politicians filed a claim at court and it blocked announcing their names.
It is absolutely logical something similar to happen in USA as these protests are becoming very irritating for much Americans, and Trump is becoming a hero of mid common people against rich, drugged and arrogant movie and music stars.