Show me ANY restaurant whose soup isn't salty. Don't think you should pick out Panera. The soups at Crispers are salty, the soups at Olive Garden are salty. It's even tough to make a soup at home that isn't salty.
You can look up the nutritional value online for most chain restaurants. In fact if you look up Panera's:
http://www.panerabread.com/pdf/nutr-guide.pdf you'll notice that many of their sandwiches have more sodium.
Also remember that many people do not have sodium restrictions and even those that do it is usually around 2g per day. Very restricted might be 1.5g. So go ahead and have that less than 1g soup (they have 8 that fit the bill). But be careful what else you have for the day
Crispers:
http://www.crispers.com/Nutrition.aspx?xid=7
Olive Garden:
http://www.olivegarden.com/menus/gar...nformation.asp