Marchers opposed to Chief Executive Leung Chun-ying were eager to declare their reasons for protesting, but many of the thousands who turned out to support the administration were reticent.
Several participants replied "no comment" when asked to explain their endorsement of Leung at a morning march from Central to government headquarters and at a carnival-style rally at the same venue in the afternoon.
An investigation by Chinese online news portal The House News , which sent reporters undercover to join the rally, suggested one possible motivation - cash handouts of HK$250, given to those taking part in the morning event by an operative hiding inside a portable toilet. The New Territories Association of Societies, one of the co-organisers, said it had filed a complaint with police over the pay-to-protest allegation.
Executive Councillor Cheng Yiu-tong, convenor of march organiser Hong Kong Celebrations Association, said: "The attendants are the silent majority, and we hope society will move forward, prosperously."
Patrick Ko Tat-pun, convenor of the afternoon rally, said he intended to counter "China- and Hong Kong-hostile" mobs. He said a row over illegal structures at Leung's home, which fuelled attempts by the pan-democratic camp to impeach him, was a "trivial matter".
Both organisers said Leung should be given time to focus on policy implementation and criticised pan-democrats' attempts to obstruct the administration.
Slogans were chanted, placards raised, and national and Hong Kong flags waved, but not all of those in attendance were as certain of their backing for Leung as their leaders.
Retired civil servant Wong Wing-sun said he joined the rally to "support the government, support China", stopping short of mentioning Leung.
Warehouse worker Ming Chuen-hoi said: "I came here only because I'm sick of pan-democrats, who basically oppose everything the government proposes."
One Mrs Wong, who joined the morning march, said: "I support CY." When asked why, she replied: "No comment."
Liu Wing-man, waiting under the flag of the Beijing-loyalist Federation of Trade Unions, said: "We're all Hongkongers. We should unite to support the chief executive."
Tim Lau, 60, said: "Many livelihood issues must be solved by CY now, and no obstruction [by pan-democrats] is acceptable."
Marchers whom the Post spoke to denied they had been offered incentives to take part - such as cash gifts or free meals - and insisted they were "self- motivated".
The House News said its staff and other marchers were handed cash by a worker in the portable toilet. Earlier, pictures posted online showed messages delivered over popular mobile chat-application WhatsApp recruiting "paid workers" to march.
Cheng reportedly dismissed the website's accusations and accused "opposition camps" of a smear.