(For calendar events) If the routesheet specifies a particular cafe for a control but there are other shops/pubs etc nearby (as in on the same street), can you get a receipt from elsewhere and use this as PoP?
You'd have to ask the organiser why they specify a particular café. Could be any number of reasons.
For the Uckfield control on the Oasts & Coasts 300, the organiser leaves a sheet of stickers on the counter at the specified café, so you don't actually need to spend any money there to get your proof of passage, nor do you have to worry about being held up by queues. I'm sure he would accept a receipt from a different shop or café in town, but I do stop at Poppies because it's a decent, reasonably priced breakfast and service is super quick, even when busy.
On the same ride, for the Deal control, I used a shop in the town centre, rather than the one specified on the routesheet, on the edge of town. My receipt was accepted as PoP by the organiser, no questions asked. I think in that case the shop is specified because it is on the route (the one I used is slightly off route).