Hi,
Surely not in the product page ; it is not related to the product but to the vendor itself.
And regarding your request, it is not something which will be available directly in HikaMarket but thanks to a plugin.
The fields could be vendor custom fields without any problem ; the plugin should add some content in the product page and could interact differently depending his settings (not authorize the product to be bought or just display warning).
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.