swapping harddisk too frequently will raise an alarm of suspicious gamertag achievement/gamesave tampering attempt.

Then you'll in a watchlist and once they got the clue of above said tampering, your GT are dead.

Maybe it's nothing wrong to you, but it's very wrong to M$

it's not confirmed by Microsoft, but I don't think it's a rumour

Read this & this

This also might means using a public HDDSS.bin to mod harddisk might get the hammer one day.

and I did one