Boolean values are not strings

Boolean values are not strings and are therefore never enclosed in single quotes. For example, whether you use the basic macro format or the advanced macro format, booleans are always written true and false, not 'true' and 'false'.

However, string values are converted to boolean values within a boolean context (see Conversion to boolean). Therefore with the advanced macro format you could enter the string 'true' within a boolean field because the macro editor would convert the string 'true' to the boolean value true.