It is possible that Amex receives some sum less than $500 from Vanilla when you do a reload, and makes it back in float and breakage, and therefore loses money when all you do is load $500 and immediately use it. They would prefer you to use it as a checking account. That is why they give you free ATM withdrawals if you direct deposit. That probably also costs them money when you game that by doing a $1 transfer from Paypal every month. If they required $500/month like most banks for free checking it would still be worth it to split direct deposit between that and real accounts for those interested in miles so that's probably why they don't limit it.

But, as there are no reports of shutdowns and they are limiting any possible losses with the $5k/month limit, I will continue to max it out as long as they allow. The only thing I do really to 'avoid' a shutdown is pay off other CCs first before the ones I use to buy VR because it costs me no extra effort. Sometimes I pay the same CC if that's what's left to pay but not the majority of the dollars since I usually have some reimbursed business travel expenses on a different card to pay. I don't buy VRs with Amex cards, but that's just because I have better rewards elsewhere. I also pay my rent with it and withdraw $500-1000 from an ATM each month. I give them a little float, but not much.

I have no way of knowing if these minimal efforts make any difference, but they have negligible cost to me. If anyone out there is not maxing out the full $5k potential of this card out of fear of being shut down, you are probably acting irrationally with all the other people who do it with no problems. When eventually you can't buy VR with a CC you will be locked out just like everybody else only you won't have earned as much while the gravy train was rolling. And if by some chance Amex did start closing Bluebird accounts, you have no way of knowing if your measures are going to be enough. This is why the Cardinals prefer to spread fear, uncertainty, and doubt and won't tell you directly what the limits are to trigger things like an FR, and probably also have some random element to it. If they tell you the limit, you will do just under it. If they leave you guessing, you're likely to restrain yourself more than they would have made you. I think some on this forum and other websites related to maximizing rewards might also have a motive to spread FUD given what happened to the Mint deal.