Couple items is not good evidence at all, because the SHIPPERS hand them couple items seperately.
Shipper fans will go give Tiffany one item and take pictures of her wearing it. Then go give Nickhun one item and take pictures of him waring it. Then put it together and post on Internet forums "OMG look they have couple items!".
The super annoying WGM fangirls shipping Yonghwa-Seo are doing that shit all the time.