No, never. If you do, there’s a high chance it won't work.
To keep our service secure and to prevent fraud, we have an authentication process that takes place the first time a tag is activated and registered to an account. This isn’t transferable and we don’t re-issue authentication codes (contained in the packet at purchase).
Furthermore, many of our tags simply aren’t designed to be removed and refitted, and for good reasons. This all means the resale of used tags isn’t something we support, and not just for financial reasons, because it’s likely to end in a negative user experience, or something failing when you needed it the most.