So, I just confirmed, if you upload a TCX file generated on a non-supported platform onto a supported platform, it will sync and you will be awarded smoothie points. Tested with Nike+ (not supported for ages - unaltered source file - incidentally with HR) to Garmin Connect. This has always been the case and continues to be so after the 2nd of April.
This means that you can (still) earn HR or normal points with the following platforms (even if now unsupported - I did not test all platforms or all source devices but they use the same mechanism) if you export a file and then import it onto a different supported platform:
There is no hacking or reverse engineering or cheating or any altering (whatsoever) required. Getting angry when educated about this useful feature (esp for Adidas and Nike users) is just embarrassing - even more than suggesting 'reverse engineering' human readable open standard files and making apps to upload 'fake data' (unnecessary given the website will do this for you) and also saying 'moot' a lot like Mr Joker here:
Commence maximum roid raging/back-tracking/damage control.