Question about SignalR

I am connecting to websocket server using url with query data of group name to which user want to connect to: https(:)//localhost:5001/hubs/groups?groupName=${groupName}. On connection I make sure that group exists in database and userhave access to this group. Is it save to assume valid data, so every time client invokes method, to skip the part of checking in database that group name is valid?