"Heavy RF environments" hmm, lets see... Ah, something like your backyard?:
Well, no, well actually yes come to think of it, but not what I meant.
Back in the '90's and 2000's a lot of the Internet stuff was also closely related to the amateur radio community, so I was often working in buildings that also had lots of radio gear, etc.
But come to think of it at the house we're very near one of the region's largest radio antenna arrays (five towers), plus we're within a mile or two of several others. When we first moved in here, the phones took on all new and interesting hold music characteristics while not actually being on hold, and some other problems became apparent too. Damn modern gear, insufficiently shielded! I never got around to running conduit for voice/data through the whole place, but when we remodel rooms and rip open walls, I still add boxes and conduit because it is so convenient. Nice thing about having all the tools to do a job right. Going full VoIP fixed the RF issues.