Shellac has a bad reputation for water marking, but it’s actually impossible to water mark a shellac finish, except with very hot water, unless the shellac used for the finish is old when the shellac is applied, or the shellac on the wood has aged considerably.
As shellac in liquid form ages, it degrades and becomes more susceptible to water marking when applied to a surface. The deterioration is slow. You should probably think of doing some tests on scrap wood if you want to use shellac that is more than a year old on a critical surface such as a tabletop. Or better, just use freshly dissolved shellac.
As with all finishes, shellac dried on wood becomes more porous as it ages, so watermarks become more likely if sweaty glasses are left in contact with the surface. Because shellac was almost the only finish used before the 1930s, it is the finish that has been water marked the most. This is the reason shellac has been saddled unfairly with a reputation for easy water marking.
The picture is of watermarks on a half-century-old lacquer finish. All old finishes are susceptible to water marking.