Is there any good way to receive purchase order by mobile device without scan a purchase order?
I do not believe it is possible to remove that level of granularity from the receiving process. There are upstream transactions (first, the source PO, then all other transactions that Master Planning will have pegged against that supply) relying on the Receiving group to report back that not only Item X has been received, but specifically that Item X has been received against expected supply from PO Y.
I'll expand on the scenario you laid out: if we have 3 PO's outstanding--each containing Item X, among others--it is feasibly possible for each of those PO's to be sourced from different Vendors and each to be expected to arrive at different times. A shipment arrives, and let's say it was possible to only identify your receipt by item number or Load ID--how will your receipt work inform Procurement of the fulfillment status of each individual PO (which one was it for?), what would quality do if they have specific incoming inspection requirements for each Vendor, and how will Accounts Payable know which PO is received/partially received and ready with an invoice?
On the other side of the workflow (once you've received your respective PO's), there is a way to aggregate your items into License Plate groups to simplify your put away process.