How common is it for the top seam around a can to develop a leak when shipped? A friend sent me 12 Heady Toppers USPS next day. Each 4-pack was placed in a zip-loc freezer bag with a big wad of paper shop towels, then bubble wrapped and packed in a box with more bubble wrap. No cold packs were used. 3 of the cans had a teeny tiny leak where the tops are sealed on. Hardly any got out, but I chilled them and drank them later that night with a buddy before they lost all their carb. I guess they couldn't take the pressure from the hard ride - they were hard as rocks! So...anybody see this before? Is it a canning line issue? Many beers are shipped the world over and I've never seen them leak. Thanks in advance.