I've actually been doing this for the last two months without incident. There is NO cap limit with my card swipes or the amount of points earned. I was upfront with my plan when I opened the account. Theres nothing against the T&Cs in doing this. They even allowed me to raise my ATM withdrawal limit to $1000 per day so that I can transfer funds. I'm averaging 6,500 points per month, but part of that is due to the fact that I was in Europe for 2 weeks and couldn't swipe with an international data plan. My goal is 10,000 points per month.
I have to pay 2.75% per transaction, which works out to $0.03 per $1.00 transaction. I use the Square app.