T & P
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Hashtags and social media accounts are extremely common across all kinds pubs and venues, including many that no-one here or elsewhere would describe as catering for the well off or trying to drive off the well less-off.Think you are deliberately missing the point, granted nuff people of all backgrounds will use contactless....but "#thefuture" will resonate deeply with someone who feels the need to read a trendy bars Twitter feed.
If a place like The Beehive or The Dog Star or Hootanani writes about an upcoming gig or promotion on a blackboard, or a poster in the toilets, and include a hashtag or simply asks the reader to check their website for further details, is that any different? The great many people who can't afford a smartphone will surely feel as unwanted/ redundant as those in your scenario.
Hell, Wetherspoons now have an app that allows you to order drinks and food from your table and have them delivered to you. I suspect Spoons customers who can't afford a smartphone will feel far more unwanted and Being treated as second class by their local when they see other patrons avoid queues at the bar and have their pint delivered to them while they have to do it the old fashioned way, than any poor patrons of the C&A would feel at the sight of that hashtag. So in your view it'd be fair to say Wetherspoons are discriminating against the poor or trying to change their client demographic?