"Whilst the syntax for expressing sequences and combinations of events is concise and can be used to meet all the requirements, it is not always obvious how to express a sequence of events that is very simple in natural language. It could be compared to designing a program using assembly code. For example, in order to express the event of visiting a specific page for exactly the third time in a session, two conditions must be checked for: that the page has been visited at least three times and that the page has not been visited more than three times, as demonstrated in the example XML file used in the verification of functional requirements.
A more expressive way of specifying event listeners would improve usability although there is a trade-off to be made between simplicity and over-specification. as the XML schema could become bloated."
~ Mitchell, R. (2008)