In a city such as Washington, where being instantly reachable can be everything, carrying five cellphones might not seem unwarranted. But unfortunately for someone found over the weekend with that many, at least three of them belonged to other people, according to D.C. police.

The three rightful owners were at a bar late Saturday or early Sunday in the 2400 block of 18th Street NW, in the Adams Morgan neighborhood. Police were called in and made an arrest after someone spotted the phones being lifted one by one from the patrons, who apparently were unaware of what was happening.

Cellphone robberies have become a scourge of life in the District and throughout the United States. The devices are small, widely used, easy to conceal and valuable.

Early Saturday morning, another such theft occurred while a woman was at a bar in the 900 block of U Street NW, in another of the city’s entertainment zones, according to a police account.

The phone was taken from the woman’s purse, the police said. An arrest was made.

The weekend thefts appear similar to problems reported last year in the Georgetown area. Police warned then that thieves had been snatching purses and handbags as they hung from the backs of chairs in restaurants and nightclubs there.

In some cases, police said at the time, the thieves made off with wallets or smartphones from bags while leaving the bags in place.

Usually, victims do not know what has happened until they prepare to leave and need to pay the check, the alert said.

The weekend thefts prompted police to issue new reminders calling on restaurant and bar patrons to safeguard property, remain aware of their surroundings, and carry as few valuables as possible.