Interesting that Garmin in Netherlands also does that, it's shown to be a routine courtesy by Garmin Australia for many years now in identical circumstances, i.e. LM sub not used for more than 2 years and device transferred from original buyer as per the 'fine print' defining what constitutes the 'lifetime¹' or 'useful life' of a device:
¹If you purchase a nüMaps Lifetime subscription (sold separately) or if your Garmin product comes bundled with a nüMaps Lifetime or other lifetime map subscription, you will receive map data updates when and as such updates are made available on Garmin.com during the useful life of 1 compatible Garmin product or as long as Garmin receives map data from a third party supplier, whichever is shorter. A product’s “useful life” means the period during which the product (a) has sufficient memory capacity and other required technical capabilities to utilize current map data and (b) is capable of operating as intended without major repairs. A product will be deemed to be out of service and its useful life to be ended if no updates have been downloaded for such product for a period of 24 months or more. Unless otherwise stated, the updates you receive under the subscription will be updates to the same geographic area included with your Garmin product when originally purchased. In some instances, your Garmin product might not have sufficient memory remaining for you to load an update to the map data, in which case you will need to either (a) select reduced map data coverage for your updates, or (b) purchase separately a microSD™/SD™ card (if and as applicable to your Garmin product) and load all or a portion of the map data coverage for your updates to the card and insert the card into the microSD/SD card slot contained in your Garmin product. If neither of the measures in (a) or (b) can be used to address your product’s lack of sufficient remaining memory, then Garmin may conclude that the “useful life” of your product has expired. Garmin may terminate your nüMaps Lifetime or other lifetime map subscription at any time if you violate any of the terms of this agreement or your subscription. Your nüMaps Lifetime subscription or other lifetime map subscription may not be transferred to another person or another Garmin product.
If asked, i've never known Garmin AU to continue to enforce either of those separately or in in combination despite reports from users in other parts of the world that they do. A couple of old sayings come to mind: 'The squeaky wheel gets the grease' and 'No hide no Christmas Box' .....
Please Login or Register to see the links
A footnote: I always factory reset any 2nd hand Garmin i purchase before connecting for updates of any kind. Sometimes [if the device has previously NEVER been connected for updating since purchase] that results in a non-LM device being given back it's 90 day nüMaps guarantee and for LM devices overcomes any possible problems with continuing LM entitlement.