They have every right to raise rates if they want to.
But the key here is to properly inform drivers of this temporary
hike. This is what the Millenia Walk management claimed to have
done back in 2009 during the Comex fair. They claimed, sufficient
notice were posted and the 10 minute grace period gave drivers the
option of leaving the carpark.
This time, there were NO signs at the carpark entrances. Drivers
were 'tricked' and not given ANY choice.