When a VQL contains an attributes that uses the reserved keyword, it must be surrounded with the double quotes, if not, your VQL deployment will be failed with the following error.
> Syntax error: invalid identifier: 'trailing' (reserved keyword)
However, when such attribute is surrounded with the double quotes, it is not mandatory to use ESCAPE keyword in wrapper definition and also it will not fail during the query execution.
To know the list of reserved keywords, refer to the [Basic primitives for specifying VQL statements](https://community.denodo.com/docs/html/browse/7.0/vdp/vql/language_for_defining_and_processing_data_vql/syntax_conventions/syntax_conventions#basic-primitives-for-specifying-vql-statements) section of the Virtual Dataport VQL Guide.
Hope this helps!