O. Special Handling of Undeliverable Packages;
Refused Packages Returned
1. Domestic packages refused by the consignee, or which cannot be delivered due to any other cause beyond UPS’s control,
will be returned to the shipper at shipper’s expense. A package returned to the shipper after delivery is subject to applicable charges. The UPS Service Guarantee does not apply to undeliverable packages returned to the shipper.
2. If a domestic package is refused by the consignee or for any other reason cannot be delivered, and return of the package is refused by the shipper, or the package cannot otherwise be returned to the shipper, UPS will retain the package for a reasonable period of time, to be determined in its sole discretion (not to exceed thirty days), and UPS reserves the right to dispose of the package thereafter.
This comes from the document known as the UPS TARIFF/TERMS AND CONDITIONS OF SERVICE.
I called UPS about this, after an attempt at service by UPS.
Not only can you refuse to accept delivery, the Shipper has to pay to have it shipped back.
