at least in some parts of the world they are...
The Hungry Ghost Festival is celebrated by Southeast Asia's Chinese communities ( and that means Malaysia too, where it's called Phor Thor) during the seventh lunar month on the Chinese calendar ( i.e. roundabout August ).
Before the family became Christians, we would follow our grandmother as she celebrated this "festival". Apparently, the deprived ghosts in hell get an entire months' vacation from purgatory.
(Even as a child, I would wonder why the ghosts would so obediently go back into Hell after the one month "vacation" )
To appease these roaming and wandering ghosts, there would be offerings of food, music, theater ( yeah, a time for chinese opera and screenings of movies outdoors - kinda like drive-ins with the smell of burning incense and joss sticks, as well as the smoke from the burning of "hell money/notes" thick in the air).
***When we were younger, we were told that the ghosts would "smell the smoke" and get full from the scent, as well as if the hell notes were burnt, they would somehow be "interdimensionally" forwarded to dead relatives etc.***
If they weren't kept full or entertained, they would come into your house seeking food, wreck havoc and start messing with you...and they especially loved getting to the children - so there were a lot of taboos during that month, like no swimming or the spirits in the water would drag you down; or going out late at night; don't start answering calls to your name if you don't see anyone around; if you smell sweet scents in the air, keep it to yourself and don't even mention it to anyone;
AND if for some reason, you felt the need to pee outdoors, like in the bushes or something, you had to say aloud "Excuse me, please move aside" before you started peeing. ( kinda like a forewarning so that the spirits wouldn't get peed on and get mad at ya)
When we were growing up, there was an open lot in front of our house, which was THE designated place for offerings yearly, and a tent would be put up and families from ALL AROUND would come with their offerings, placed long long tables and with little colourful "hungry ghost festival" flags stuck among the different types of food. There would be lots of tales like, if you bent down and looked through to the back between your legs, you would see a ghost, yada yada yada...
I don't remember this particular occasion, but my mom once told us that when my older sister and I were toddlers, she had brought us out to the playground, and we had come running to her telling her that some "auntie" was beckoning at us and asking us to go with her. When my mom looked at where we were pointing, she didn't see anyone........