There is a blurb at batteryuniversity.com that says storing lithium at full ~4.2v/cell charge promotes cell corrosion (on the anode IIRC). Now, that's for Li-Ion, but doesn't say either way about lipo specifically. However, I would question why manufacturers would ship lipos at ~3.8c/cell if it wasn't an issue. Plus, many battery chargers have the storage mode. Could be just marketing, but I tend to err on the side of caution. I don't think they'll puff or blow or anything, but might affect capacity over a shorter number of cycles.
I would question why manufacturers would ship lipos at ~3.8c/cell if it wasn't an issue.
I almost think that is strictly for safety reasons, should a pack get punctured or shorted in transit. Good question, it's hard to get definitive answers...