Ex EE here (RF/mixed signal). I always modelled it as everything being connected to everything via a tiny capacitor and a big resistor in parallel. This allowed

Ex EE here (RF/mixed signal). I always modelled it as everything being connected to everything via a tiny capacitor and a big resistor in parallel. This allowed a few odd scenarios to be reliably identified, especially in UHF frequencies and above. The trailing capacitor just had a large value invisible resistor attaching it to your circuit somewhere :)