Alastair Roberts (PhD, Durham University) writes in the areas of biblical theology and ethics, but frequently trespasses beyond these bounds. He participates in the weekly Mere Fidelity podcast, blogs at Alastair’s Adversaria, and tweets at @zugzwanged.
Fencing the offering plate is a good idea, and biblical. But what does he mean by “young child participation in the Eucharist?” In the context, it sounds like he is still advocating “credo-communion” rather than true paedocommunion. With regard to paedo participation in the Eucharist, the accountability and credo of the parents is enough. “Giving offerings unworthily?” By ourselves, none of us is able to give offerings worthily, but if we have been absolved of our sins by Messiah’s perfect sin offering, then we have been made worthy and we must dedicate ourselves to Yahweh as whole burnt offerings, following which we participate in the peace offering (i.e., the meal in the holy of holies). There is both continuity with the OT sacrifices and also development, of course. Since the offering and the Eucharist are a package deal, both should be fenced off. It does not make good biblical sense to allow a person to participate in only one but not both of those things.
Ad`ver`sa´ri`a
Alastair's Adversaria 
Fencing the offering plate is a good idea, and biblical. But what does he mean by “young child participation in the Eucharist?” In the context, it sounds like he is still advocating “credo-communion” rather than true paedocommunion. With regard to paedo participation in the Eucharist, the accountability and credo of the parents is enough. “Giving offerings unworthily?” By ourselves, none of us is able to give offerings worthily, but if we have been absolved of our sins by Messiah’s perfect sin offering, then we have been made worthy and we must dedicate ourselves to Yahweh as whole burnt offerings, following which we participate in the peace offering (i.e., the meal in the holy of holies). There is both continuity with the OT sacrifices and also development, of course. Since the offering and the Eucharist are a package deal, both should be fenced off. It does not make good biblical sense to allow a person to participate in only one but not both of those things.