@djinn I use an app called PlugShare. It allows us to list spots for a whole range of outlets from the high power DC Fast chargers to the simple wall outlets. It is used for electric cars owners. You can set the filters to show only 110 or 240 outlets but most posters will only show outdoor plugs that are accessible for cars. If someone were to post a wall outlet inside a Starbucks coffee shop, that would give the false impression that an electric vehicle could go there to charge (albeit very slowly). So that is the flaw in using the PlugShare app unless the poster makes a special annotation that the plug is situated INDOORS for charging electric skateboards and OW's.
Normally, i don't have many issues finding a charging location at coffee shops and fast food restaurants. Where I have issues would be out in the parks and outdoor trails. That's where the portable battery packs come in handy. I plan to order one next spring so that I can go for longer rides.