My takeaway is that Garmin could probably stand to put a layer on top of this to stop it being embarassingly accessible while continuing to keep the data in ope

My takeaway is that Garmin could probably stand to put a layer on top of this to stop it being embarassingly accessible while continuing to keep the data in open user-readable standards. This could be as simple as "(optionally, default do) prompt for a PIN on the device when mass storage / MTP is requested". I don't find Apple's watch offering compelling, but I can appreciate that it won't just dump all your data e.g. at a customs checkpoint.