Purpose and limitations, if any, imposed by Service Tags?

Does an XPS Service Tag ever impose any hard limitations within a system's BIOS which allow/disallow features regardless of the features actually available, or is a service tag purely a "cosmetic" code that is tied to the owner and their equipment which allows easy identification of both the owner and their specific configuration?

I'm asking because... If replacing an XPS motherboard with a used one from an online purchase, should one be concerned that a used motherboard may have a service tag which cannot be changed, or would that be merely some "aesthetic" issue (i.e., not hard BIOS lock on any features), perhaps a number mismatched to the actual configuration?

Likewise, do some used XPS motherboards come in such a way they require a service tag, and if so, will one have to enter such when first booting? In that case, what if a tag matching the motherboard/configuration is not available?

Some people have reported needing to change the service tag, or set it, upon first boot, while others have not reported such, and in all cases, it's unclear what service tag they are using. In one case, it sounded like a used (or refurbished) motherboard came with a new tag... that seemed weird though since a tag, it seems, would relate to a user/owner and the system's greater configuration (not just the motherboard, but beyond the mobo). In that particular case, it was unclear where the tag came from so perhaps this was some ad-hoc thing the hobbyist did.

All of this caused me to search around but I cannot find any information as to whether service tags (possibly incorrect tags) ever present any BIOS-related hard technical block or problem, or if they are merely/always a support thing, where, if mismatched after warranty, do not present any hard blocks/issues beyond "cosmetic" disparities between an actual configuration and, perhaps, an incorrect configuration represented by a stale service tag. (?)