I'm curious--What are the possible ramifications of manufacturing spending? It is fully legal, right? Is there any risk to it?
Yes, it is fully legal. The risk is that the credit card company makes note of your pattern of manufactured spending and closes the account, clawing back any and all points (since their relationship with you is voluntary and they can opt not to do business with you at any time). At worst, they could close *all* your accounts with them and claw back any points they have control over. This is why it's always best to mix in genuine spending with manufactured spending. I put all my regular spending on cards when possible, and make sure to choose the right card if there's a category bonus to be had. In this way, you can at least make a case that your pattern of spending is legitimate if necessary. Some people do their manufactured spending in unusual amounts to limit the risk of a review.
I've had a nice run of non-MS points lately as I'm consulting for a company that's just setting up a physical office space-- I've put thousands and thousands in needed office supplies on my Ink Bold at 5X points per dollar-- racked up about 100K Ultimate Rewards points in the past two months.