Writing 250+ free articles isn't enough of a tithe for her?
The free help is basically what Erin's blog and these forums are for. If she's going to help people for free, I think the one-to-many approach of writing articles that will remain online indefinitely is the most effective choice.
Nevertheless, Erin actually does give free readings now and then, but not by request. She picks and chooses those situations herself when she believes it's a good idea. If she were to formalize this process, it would just make things unnecessarily complicated.
Erin has found that people who get free readings (or gift readings paid for by others) often don't make very good clients. Since they have no personal investment in seeing the reading succeed, they'll often ask trivial questions instead of focusing on their core issues. Afterwards they won't even bother to apply the guidance they received. So unfortunately it tends to be a waste of Erin's time to offer free readings, especially when they displace paid readings (meaning that Erin effectively ends up paying for it). This doesn't always happen, but I'd rather see her work with people who are serious vs. casual and uncommitted.