No, tickets are not applicable as Modern Vlissingen Square is a free, open public space and not an attraction requiring admission.
There is no ticket office or admission requirement for Modern Vlissingen Square. As an open public area, it is freely accessible to everyone at any time. Visitors do not need to purchase any tickets to enter, walk around, or enjoy the ambiance of the square.
Any purchases made on site would relate to goods or services offered by the independent shops, cafes, or restaurants surrounding the square, which operate independently and are not part of the square's access. Therefore, arriving without pre-purchased tickets or an intention to buy them on site is the correct approach for visiting this location.