There's precedent for it, sort of, in American history. In times of war long ago one could hire a proxy to volunteer on your behalf instead of going yourself.
And if you really reflect on it for a little while, you'll realize Christians who believe in infant baptism practice this already in a way, having the sponsors, aka the godparents, answer for the child in renouncing the devil and all his works and all his ways, etc. in the baptismal liturgy.
So the satirical scenario here in the style of The Onion is not only humorous but plausible, but I think it made the mistake of having the hired rep accompany the introverted Ms. Ivory to her church.
It would have been funnier if the rep were simply paid more and "Ms. Ivory" remained safe at home. The truly liberated introverted Christian, after all, can probably get away with that in these times.
She could probably read the newsletter online, listen to the sermon by podcast, and tender her offering through PayPal, without ever having to suffer the trauma of human contact or the long recovery period required afterwards.
And just think. For the Christmas and Easter Christian, she saves a lot of dough because she only has to hire the proxy for two days, and the proxy gets the added bonus of breakfast on Easter included!