Sellers should not drop FedEx Ground Economy (SmartPost) packages with USPS. It doesn't matter that FedEx transfers to USPS for second leg of delivery some of the time or that there may be USPS info on the label. Always bring those packages to FedEx.
This was announced by the carriers last year, effective July 14, 2024 - eBay posted an alert on this forum (link).
USPS can and does seize those packages.
Reports have been increasing of USPS enforcing this rule. Tracking will say something like unpaid postage or counterfeit postage (because postage was paid to FedEx, not USPS).
When packages are seized because they were left with the wrong carrier, the seller is responsible for refunding the buyer.
USPS sign: no UPS, no FedEx
