(Portland, OR)  --  Tipping may eventually be a thing of the past at most Portland restaurants.  About a half-dozen restaurants in the city are so far adopting a "no-tip" policy, replacing tips with fixed gratuities charged to customers as part of the price of the meal.  Restaurant owners who are adopting the policy are affixing stickers at their establishments that indicate the eatery is a "no-tip zone."  Restaurant owners tell KOIN-TV the policy is, in part, a way to help them stay in business in response to a new minimum-wage hike.