The Theory of the 7th Month

As most of you know, the Hungry Ghost Festival has officially come to an end by midnight tonight. Today is the last day of the 7th Month of the Lunar Calendar and the general belief is that the Gates of Hell close today. My dad is a Buddhist, and so before I went out today he reminded me to come home before 12 midnight because he was burning joss and paper money or something along those lines. Now, as most of you know, I don't really believe in such superstitions but I conform out of respect for my Dad's religion.

So, as I was driving back home today (at 11pm), I was speculating as to exactly WHY did I have to be home by midnight? My friends (whom I was giving a lift back) said that it's because the Gates of Hell close today and the hungry ghosts who are unwilling to go back to Hell will seek souls to possess.

So my question is, if let's say I go home at 12 midnight, can I come out again after 12?
Hurhur. I know, many of you are slapping your foreheads going, wah lau... nocturnal sia... incorrigible lah this girl...

I mean, if the Gates of Hell close at 12 midnight, then doesn't it mean that all the ghosts would have gone back to Hell already? So there's nothing to fear if you go out after 12 right?
Then my friend said, 'Well, if that's the case then we shouldn't even be going home now because now is rush hour for the ghosts... All of them are rushing back to Hell right now! If we go home too then we'll bump into them...' And yes, that theory makes sense too if you think about it. So do the ghosts take time to get back to hell or is it the case whereby at 12 sharp they all go