For a long time, people would buy established accounts for the sake of promoting a new coin or token - which were often scams - to make it looks like reputable members of the forum were endorsing them. This is originally why some DT considered the act of purchasing an account to be redtag-worthy.
Nowadays people buy these accounts mainly for the purpose of enrolling in a signature campaign. They take the earnings they have made from sig campaigns and re-invest them in the purchase of a second, third, fourth or fifth account. So I highly doubt this member is at all "new." They probably have multiple accounts currently enrolled in campaigns.
Do you think if they are "only" going to participate in signature campaigns they are not worth the red tag? Or maybe just a neutral tag? If they want to do it honestly they can build up an alt account, but that takes time without getting money for writing. I would say that if they are able to get enough merits, and nowadays it is not that difficult with the number of review threads and that are offered, also forum members like The Skeptical Chemist, in about 8 months they can start getting paid with Mr Member rank. There doesn't seem to be a lack of campaigns lately either. I think it is very benevolent to assume that they are "only" going to participate in signature campaigns when they are bypassing the merit system.