Unfortunately, there are no definitive visual sign of poor provenance but the best thing to do is take the time to examine the bottle in detail. Below is a small list of what you should be looking for;
The technical term for lost (or unfilled) volume in a bottle, barrel or tank is 'ullage'.
Neck: Normal level for all wines. In wines over 10 years of age, this level suggests excellent provenance.
Base Neck: A common fill level at which many châteaux release their wine. For wines of any age, this level suggests excellent provenance.
Top Shoulder: Again, a common fill level at which many Châteaux release their wine. For wines of any age, this level suggests excellent provenance.
Very High Shoulder: Acceptable fill level for wines 8 or more years of age. Suggests proper storage conditions throughout its life.
High Shoulder: Usually not a problem for wines in excess of 20 years of age. This level may be caused by easing of the cork combined with natural evaporation. Check the clarity and the colour of the wine in the bottle as a secondary indicator of provenance.
Upper Shoulder: Refer to High Shoulder and Mid Shoulder level descriptions.
Mid Shoulder: May suggest ullage during the life of the wine due to either easing of the cork or inconsistent storage conditions. Not abnormal for wines 30 or more years of age. As additional indicators of risk, definitely inspect clarity and colour of the wine in the bottle, as well as condition of the cork.
Low Shoulder and Below: Suggests poor provenance. Definitely a risk and often not saleable, with exception given to rare bottles and is not recommended for consumption.
Liquor Act: It is an offence to sell or supply to or obtain liquor on behalf of a person under the age of 18 years. Liquor license No. LIQP 770010066