(I work at Sift Science.) One thing to note -- our system analyzes a whole bunch of patterns for each user. So just shopping at 3am by itself won't cause probl

(I work at Sift Science.) One thing to note -- our system analyzes a whole bunch of patterns for each user. So just shopping at 3am by itself won't cause problems, nor will using a prepaid gift card by itself. But if a user matches multiple fraud patterns, then they're likely to get a high fraud score.