If I spend over 150$ I'll pay fedex or ups just to get a LAG. This isn't a screw up though there are entire states that don't offer overnight delivery on express shipping, PA is one of them. It doesn't matter what time the package arrives in my post office the next day, it is the Policy of the carrier the seller choosed not to deliver the package in a time frame that would comply with the terms of that sellers LAG. My point is more towards people who try to force express on there buyers and I just avoid those sellers for these reasons anymore.I would do express for a large order, but that's only due to the LAG.
Also, when shipping reptiles, the seller generally guarantees live arrival even if it takes longer than 24 hours and even in times of carrier error. The tarantula hobby is the only one I've seen people's LAG become void if the carrier screws up. I don't think that should be on the purchaser, and is a risk that any seller needs to take. Until the package is in the hands of the buyer, it is the seller's responsibility IMO.