Hi,
I want to say that everything is possible but it will require development.
The UPS (and USPS, Fedex, etc) shipping plugin uses the user address to determine the shipping costs.
It could be possible with some modification in the system that the user could enter an address when he isn't logged but it will touch some HikaShop core files.
It is not a simple modification, it requires good development and PHP skills.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.