First, electrical outlets are a premium feature of establishments. Then, a luxury for customers. Really, we notice a person with multiple devices charging. Accordingly, looks out of place since two things are being done at once. So, plug into one outlet at a time in a cafe. Given, good netiquette to let others charge devices. After all, many people have low batteries.
It is good internet etiquette to use one plug at a time because using multiple plugs discourages customers from patronizing an establishment.
Using multiple plugs a a Hotspot prevents other customers from using the wireless service for various reasons. Patrons may feel uncomfortable asking to use a socket when someone is using two.
When customary services are unavailable at Hotspots customers go elsewhere. Patrons who use multiple plugs make themselves and the hotspot look bad.
Using one electric socket at a time if you have multiple devices to charge is reasonable. Sharing plugs with customers who need them is great.
Plug Into Netiquette
Therefore, proper netiquette to use one socket at a time. As a result, more comfortable. Given others have more room. Also, allows those afraid to ask the opportunity to use one.