Marco Russo and Alberto Ferrari make use of REMOVEFILTERS:
A DAX user-defined function, also known as a UDF, is expected to return a scalar or a table. However, because functions are fundamentally macro-expansion of DAX code, it is possible to return CALCULATE modifiers if the function is to be called only as a filter argument of CALCULATE.
To show a practical example of when the feature proves to be useful, we debug a measure that fails because some calendar filters are not being removed correctly. Fixing the measure elegantly requires creating a function that removes filters rather than returning a value.
Click through for that example.