I used mine for three $4 photo strips at the mall in a photo booth three months ago, and Chase called me almost immediately, like even before we got home. I was amazed at how quickly they flagged the activity, even for that small amount.
Fast forward to last month, and we charged a new $6500 AC/furnace on it to take advantage of the rewards. I called myself the next day to tell them that we had indeed charged that much & to not flag me. The rep told me that the charge had already posted & cleared, no issues. I'm glad, but I thought that was odd given the sheer amount of the transaction.