The security lockdown, with massive road blocks and cordoning off of areas around the venues that Mr Xi visited, also gave many a sense of separation of the Chinese leader from ordinary people.
Police arrest a pro-democracy activist (R) during a pro-democracy protest in Hong Kong, China, 01 July 2017.
What makes this unusual is authorities - not protesters - are usually the ones to make people or things disappear.
The number of mainland enterprises that have gone public in Hong Kong has skyrocketed from 101 in 1997 to more than 1,000 previous year - more than half the total number of companies listed in the city - with the market values of mainland companies rising from about 20 percent to 63 percent of the city's total market capitalization.
There was other symbolism hinting at the balance of power.
The march takes place every year but took on an outsized significance this time because it came at the tail end of a visit by Chinese President Xi Jinping, after a week in which high-profile young activists were detained for earlier demonstrations.
China's main representative office in Hong Kong, the Liaison Office, didn't respond to a faxed request for comment.
"Making everything political or deliberately creating differences and provoking confrontation will not resolve problems", the President said, adding "On the contrary, it can only severely hinder Hong Kong's economic and social development".
People related to bookstores handling books that are critical of the Chinese Communist Party have gone missing one after another.
One of the movement's leaders, Joshua Wong, was taken away in handcuffs for the second time in three days, but later released.
Hong Kong's last governor Chris Patten.
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Tanks, missile launchers and chanting troops greeted Xi in a potent display of Chinese military might Friday morning.
China's President Xi has warned Hong Kong that movements for challenging Beijing's rule will not be tolerated.
He took part in a series of lavish events, including a flag-raising ceremony, amid tight police security. Replicas of the "Goddess of Democracy" statue, a regular feature of these commemorations, have never appeared in Beijing since 1989. The key themes of the protests were reclaim Hong Kong and release of Liu Xiaobo, the jailed Chinese dissident and Nobel Peace prize victor who was recently diagnosed with cancer.
Ron Wong, 17, who was marching with his parents, said Xi's visit had been a "show of power of who's in charge".
Recently, however, independent bookstores that stock such works have been disappearing - replaced by others with ties to the mainland.
"Hong Kong is the "super-connector" between the mainland and the rest of the world".
The CBC's Elaine Chau came to Canada from Hong Kong with her family in 1992.
For Hong Kong, the focus is not whether the principle will change or not, but how to implement it comprehensively and accurately, Xi stressed.
The bridge, too, has helped cause a literal disappearance - of the endangered pink dolphins that used to swim in the Pearl River estuary it spans. The possibility of another anti-Beijing rally, such as that of 2014, when young people and other residents occupied Hong Kong's center, can not be ruled out.
Under blue skies by the harbourside, the Chinese flag was raised in a televised ceremony on the same site as it had been 20 years ago, after the Union flag was lowered.
Meanwhile, the biggest appearance of all in Hong Kong this week has been the arrival of Xi Jinping.
The swearing in function was held on the day when the territory marks its 20th anniversary of the city's handover from British to Chinese rule.
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