Gotcha. I didn't consider just putting a small amount of direct deposit into HMB, that's pretty clean! Might try it myself :) I doubt they expect most users to do something like this though, which may explain why they're able to offer a rate that high.
Absolutely. I know a number of people use this “trick” and it’s been working for me for over 6 months. I can’t remember if referral codes are allowed here but I have 2 invites which let you jump to Tier 1 (3%) right away instead of having to go up 1 tier a month (it skips waiting 3 months before you hit 3%). I used a Black Friday deal that gave the same “perk”.
Full disclosure: using my code would give me 1 “undo” or something like that. Essentially it would let me move up a tier 1 time if I were to fall for some reason. I don’t think I have any use for something like that but I always fell a little scummy offering referral codes so I didn’t want to leave it out.