Possible Clues:

• To read hastily by row is more revealing
• Check level is not so full
• Canister could be smaller
• Have a quick look at part of stadium? It's barer
• Search bank becoming poorer
• More revealing view seen on stage
• Scrutinise one who may be making a granny more parsimonious
• Look at row on grandstand less full?
• Check on bank is less adequate
• Look over a range that's less lavish