At a Meriton serviced apartment block in Bondi Junction over the course of 10 days in April 2015, the lifts were out of order, the phone lines were down, the hot water was broken and there were leaks.
At another Meriton property in Queensland in September the same year, guests had power outages, no hot water and put up with "excessive" construction noise.
When the major accommodation provider suspected many of its guests would write bad reviews on TripAdvisor, Meriton's staff stopped their customers' email addresses from being shared with the popular travel review website.
In the first case of its kind, the Federal Court has found Meriton "engaged in misleading or deceptive conduct" between November 2014 and October 2015 by supplying incorrect contact details for guests to the review site, or by withholding them.
Under TripAdvisor's "Review Express" program, participating hotels and apartments pass on email addresses of recent guests who have agreed to share their contact details.
The travel website then emails the guests, prompting them to write a review.
The Australian Competition and Consumer Commission (ACCC) investigated the practice of "masking" guests' details after a former Meriton employee went public in 2015.
"This was a deliberate and systematic process of masking or blocking email addresses from TripAdvisor in order to stop TripAdvisor being able to contact those guests and ask them for reviews," ACCC Commissioner Sarah Court told Fairfax Media on Friday.
"Meriton argued there wasn't really any big impact from this, really 'nothing to see here'," Ms Court said.
"But the judge, having heard all the evidence and heard the arguments, said Meriton intended to reduce the likelihood of negative reviews being posted.
"The overall effect of that was to create a more positive impression of those properties.
"The judge also said that if you look at the scale and frequency of this practice ... the effect it had was substantial."
The judgment also referred to internal emails which, in one case, showed staff had asked a guest to remove a one-star rating from TripAdvisor in return for a full refund.
Ms Court said the ACCC had dealt with smaller companies posting fake or misleading online reviews, but the Meriton case was the first of its kind dealing with a major operator.
"Consumers are relying more and more on these kinds of rating systems, on comparison websites, they trust them, they're looking at them, and so it is clearly misleading if those reviews are being manipulated in such a way as to create a false impression."
In a statement, Meriton's general counsel Joseph Callaghan said the decision was disappointing.
"Meriton has never denied that between November 2014 and October 2015 some Meriton staff masked email addresses of certain guests at its hotels, which meant that those guests did not receive a reminder email from TripAdvisor to review their stay.
"As soon as Meriton's managing director was made aware of the conduct, it was stopped.
"Meriton did not agree that the conduct had the effect on the consumer alleged by the ACCC, but the court has decided against us. We will review the judgment and consider all options."
