*Floater*:Could they trace it though? Or can a typical dive shop employee or owner type the serial of a reg into some database and see who originally bought it and registered it, from where it was bought and when?
I'm sure they could and probably would if you were trying to take advantage of a warranty and free parts. I'm not sure about a database, but I suspect they would call. I have some KEF loudspeakers I bought in New York and I needed a driver replaced. Took them into my local hi-fi shop and they were able to find out when and where I bought them and whether or not it was covered under warranty. It rather pissed them off that I had bought them from another dealer for $500 less. And it took a long time to repair the relationship with my local store.