What if...
... Dragons actually do gift signets to their riders?
This is just a hunch, but hear me out. While in the islands, irids say that Sliseag gifted Ridoc with ice, Tairn gifted Vi with lightning and Andarna gifted her with something much more dangerous. The reaction was something like "that's not how it works", but I actually think it might be exactly how it works - or at least how dragons try to make it work.
RY has already told us that dragons can lie about their names. What if it is not lying but actually changing their names to kinda help the magic to take the form of their liking? I have not checked this with any other dragon name, but what comes about Tairn, his name is said to be Tàirneanach (thunder). Vi's signet we all know. However, his previous rider was a siphon. Conveniently it seems that Tàirnofeach means apparently drawing, pulling (even though I cannot be 100 % sure this is true as I could find only one gaelic dictionary from the internets). He is definitely not a dragon who can just change the name he uses without anyone noticing, but if really only the roll keeper and the bonded rider hear the full name... Well, there is a possibility to change it without anyone noticing. At least if no one really studies those rolls, which kinda must be the case if the names are qualified information.
This also brings me to another point: if the names bear no power or bigger significance, why should they be kept within so few people? Why dragons don't share their names openly?
Any thoughts? Anyone who's more qualified to deep dive into the gaelic language and could tell if I'm completely off track? 😁