The observation applies to yellow lines. Unless there are 'no loading' signs/markings a driver can park on single or double yellow lines for loading/unloading to a nearby property, or picking up, setting down passengers.
However, this loading/unloading must be continuous. If a traffic warden can say they watched the vehicle for 10 minutes and saw no loading or unloading, the driver will have no lea way to appeal.
As already stated, tickets are issued instantly on red routes or in 'no stopping' areas.