Funny thing is, ingress ratings (at least at IP65 and 66) are based on the housing's ability to withstand a water jet of a given pressure, which could come from any direction... I don't know that it would necessarily have any direct relation to its sealing against standing water on a seal, which is what some housing designs may give you when mounted upside-down. I suppose, in theory, IP67 (full immersion) should handle it, but it's amazing the way water can find a way through over time.
At least in the example above, the housing is undercover, if not actually indoors. In the instances I've seen, they too were under cover, so weather sealing wasn't really an issue... but it did look awfully cheezy.
Keeping with this theme, then, I'd like to share some pictures of an install I came across a couple years ago... and yes, this most definitely was NOT a professional install.
Plastic no-name housing in the style of your standard Pelco EH-3512... but with vent holes in the bottom. Oh, did I say bottom? Not the way it was mounted:
Yup, those vents are actually open to the sky:
Obviously this thing has had some water buildup inside of it:
Good news is, the seals on the front of the housing were so bad...
...the water never rose high enough to actually immerse camera - two of these housings, same setup... both cameras still working!
Bohan: Because ingress ratings are scaled, some ratings are more 'watertight' than others. The mounting orientation of that housing, especially lower IP rated housing that could be constructed with weep vents or covered hinges.
How about 5: This is the mount the customer insisted on, for whatever inane reason. Maybe someone making the decision think it looks cool or high-tech, or maybe it's something they spec'd years before and never changed the spec because there was no need to... And yes, I've seen both these... in one case we spent years battling to find a specific discontinued housing because "that's what we've [the customer] always used", and the person making the decisions refused to be told any better. Thankfully, he was eventually promoted (yay Peter Principle) and his successor was much more receptive to change when we explained the additional cost (to them) of sourcing the old housings.
The integrator was on the last day of a big $$ install that included many L-shaped gooseneck mounts. The specs got changed at the last minute due to some overlooked code issue so they had to replace the goosenecks with new, code-compliant mounts to meet a deadline and save the job - making them look like heros to the customer (but leaving them with many [barely used] gooseneck mounts in their inventory). They then tell the transit authority customer on this job that: "The airhandler vents cause the camera to vibrate, and the gooseneck helps disperse vibration energy and keep the image still." - making them look all smart and proactive-like to the customer...