I was waiting for Boots of Elvenkind to see exactly what they did in 5e as Mearls et al advised they wanted to move back to the "wondrousness" of magic items. Given that, plus the fact that there are no explicit auditory rules embedded in the current 5e Stealth system, plus the fact that this famous item notoriously interacts with the Stealth/Skill system (and given its iteration in past editions), I was curious what we would see and what we might extrapolate from that...especially considering the hard-coding of stealth rules and skill systems in the last few editions.
I give you opaque/non-hard-coded mechanic resolution/GM fiat embedded in the mechanics exhibit A:
- The Stealth rules outline prerequisites for Stealth based on Line-of-Sight (Lightly/Heavily Obscured). They are, however, silent on the auditory requirements for Stealth (eg they do not say that you suffer disadvantage on Stealth checks on terrain or in rooms whereby the acoustics - leaves, open space with 4 sound-reflective walls - do not lend themselves toward being quiet).
- Cloak of Elvenkind specifically interfaces with the hard-coded Line-of-Sight requirements for stealth (it bypasses the requirement for being obscured).
- Boots of Elvenkind interfaces with the lack of rules for auditory requirements for Stealth (nothing about removing disadvantage on terrain or in rooms whereby the acoustics do not lend themselves toward being quiet). You simply don't make a sound in these types of environments.
Now, either they are missing a section in the Stealth Rules (about having disadvantage on stealth checks when navigating dry leaves, loose gravel, creaky floors, "operating-theatre-like" rooms with sound-reflective surfaces, etc) and the Boots of Elvenkind are missing a section whereby they outline that this disadvantage is cancelled...orrrrrrrrrrrr...this is a case of heavy GM fiat embedded in two important mechanical resolution system in the game (the Stealth Rules and the Magical Item rules)...and thus, given the weight of those two systems on gameplay, we should expect this opacity/lack of hard-coding/GM fiat embedded throughout.