Larger layouts can develop issues, especially in longer track busses due to user wiring layout and induction in long wire runs.
More importantly – DCC control systems (including some common brands) often have significant voltage spikes in their output when some things are activated due to less than wonderful design.
Add to this… quite nasty spikes from things that generate shorts on the bus such as “Frog Juicers” of all types, auto-reversers, accidental overloads or short circuits which make your system try to reset many times and the like…
As most devices and systems conveniently forget to add any form of spike management to their design to save money, this causes severe high voltage spikes at the track that will inevitably shorten loco and accessory decoder life, actually pit the metal tyres of your loco wheels and cause general harm to many things that is totally unnecessary.
ALL significant but often invisible problems. (until you run trains in the dark, when you can actually often SEE the sparks). Fortunately, the added voltage clamping and very robust filtering that is now part of DCCconcepts BSS.2 will go some way to keeping the harm these problems cause at bay.