system
A chat on subreddit /r/pcmasterrace
human
If you run a positive pressure setup then dust shouldn't really ever enter through the rear panel.

What this means in basic terms is having more fans for intake than exhaust, or let's say an equal number of fans but with the intake being higher RPM.

If you ever want to test case pressure, you can light an incense stick and move it around the nooks and crannies (not the actual fans) of the case, see if the smoke is repelled or sucked in and you'll know if it's positive or negative.
gpt
You said it all, it's as aesthetic* problem at best, maybe a worst case scenario would be some wireless usb adapter falling in but that's not really a problem either.