Players can now see who was suspended through the Endorsements icon in Overwatch.
The endorsement system combined with searching for groups based on endorsement level has completely changed my @PlayOverwatch experience. It’s incredible how quickly the player base reacted to the new systems. Thanks OW team ❤️
— Tom Labonte (@JaKaTaKtv) July 11, 2018
Overwatch players can see which players were suspended through the Endorsement system. Endorsements are awarded to players by other players after the completion of a game, and is Blizzard's way of fighting toxicity. A player's Endorsement level is shown next to their career profile and in the hero select screen in-game, but suspended players do not have an Endorsement level shown.
A Reddit user noticed the change after being suspended. The player was a level three in Endorsements before the suspension. Instead of their level reverting to one, the icon was removed entirely from both their career profile and in-game portrait.

Another Reddit user claimed after a certain amount of Endorsements, a player's actioned account will be promoted to level one in Endorsements.
It is unclear if this distinction between suspended accounts and other accounts is a bug or not, but it allows players to easily see which accounts were suspended after Endorsements were added to the game.
Photo courtesys of Blizzard and u/Mitsiee