You're right, but that's exactly what the OP is asking about, which is the topic we're discussing here.
In the US, there's no requirement to fly the Mini 5 Pro with RID when using a standard battery. So it shouldn't be considered illegal to...
I received my Mini 5 Pro from Amazon this afternoon, and it arrived exactly as described in a sealed box. The whole fulfillment process was excellent, just as it usually is when Amazon handles the order.