Zat authority enough for y'all, Jackie, CapK and Keiva?
Not for me, based on what you posted, ie., "In this case, Rena is part of a large group, shoppers who only buy things on sale, and acts like them. Therefore, who takes a plural verb because it refers to shoppers."
I certainly agree that In the phrase one of those who (orwhich or that) it is necessary to decide whether the who, which or that refers to only one or to the whole group. Only then can you decide whether the verb is singular or plural..
In the example given, I can't agree that the verb should be plural--on what basis did the writer decide this? Give me context! If the preceding conversation had been about, say, local retail economy (perhaps the speaker was referring to a survey that had been taken), yes. But if it happened to be someone who had been discussing Rena, then this could have been just a comment about one aspect of her life, and the verb should be singular. IMHO.
