I like this idea on the whole, but isn't it using a bit too much of the branding/trademarks/etc. of the company they left? You can make factual statements about your former work, like "I used to be part of the Garmin Connect team", but this is verging on taking the name with it, with a no-longer-Garmin-affiliated organization still calling themselves the "Garmin Connect team", using Garmin Connect material (logos, demo videos, etc.) extensively on their site, etc. As a now ex-Garmin set of engineers, they can't really advertise their services using Garmin's name, though it can be listed as relevant experience.