Yes, purple tags belong to higer end items. RL does make higher end item, although like the other people on here, I wouldn't be interested. If there is a purple tag item in a store without a Runway department, that means it was probably purchased at a Runway store and returned at a non Runway store. TJ Maxx doesn't have to have a Runway department in order to accept a return from that department. Also, on occasion, TJ Maxx will have an RL event or a designer handbag event or some such thing and might end up with some purple tagged items that they wouldn't have otherwise had. Not common, but it can happen.
Blue tags usually belong to a "collection", and are typically nicer items... like Michael Kors, for example.
As a side note, if you ever want to know what some of the numbers on the tags mean... the boxed in number to the top right is the date code and runs on a 24 month scale. (This year December will be 12, next December will be 24, then reboot, for example)... that's when the item came in. The older the date code, the more likely it is to get marked down. Sometimes, next to that boxed number, there will be a dash and then a single number. If that single number is a 2... that means it's got a defect. Maybe a seam is stitched wrong or the hem is crooked or something minor that got it pulled from being shipped off to Macy's or somewhere. The other numbers don't mean anything signifigant. Open box, overstock, etc.