Noteworthy experience:
Had a customer who wanted to use USB to communicate to peripherals (using a noncompliant supply voltage), in an automotive environment.
They insisted on plastic circular connectors and unshielded cables (actually the cables were shielded, but that means nothing if it's not maintained throughout the connector and harness). Mostly for cost.
We pushed back, suggesting they use a more traditional RS-485 interface, or the like. They insisted.
Come testing day, and their peripherals are dropping like flies when hit with radiated and fast-transient (EFT) interference.
Possibly, they could've at least addressed it in software (they were running a Linux SoM), but it seems their devs never got around to it, or perhaps weren't experienced enough with Linux, or were in general too heavily loaded with other activities to address it.
We had to put the guts inside shielded enclosures, with metallic connectors tied to the cable shields. That got it to pass several kV of EFT, more than good enough. (It didn't need to be quite as robust as it ended up, but there was no just-good-enough option available that was cheaper.)
The customer needed a $50 module, which would've been fine otherwise. But we ended up delivering a $200 module.
That IP66 rated EMC box sure is sexy. It doesn't even make sense when you look at it -- the gasket feels sandy, how can it seal? But lo and behold, it does indeed seal against dust and water, and it does indeed conduct very nicely (a couple of ohms between any pairs of points inside the enclosure). But that price...
Tim
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