Traditionally, Libertarians have guarded the definition of free will very closely. Libertarians don't allow compatiblists to remove essential aspects from the concept of free will, like say, reducing ability to hypothetical ability. But while we maintain constant vigilance against compatibilist reductions to free will, it seems to me we are less aware of needless and harmful additions to the concept of free will; additions that may be just as damaging as compatibilist reductions.
Both Arminians and Open Theists frequently use the term free will, but do we mean the same thing by it? Compatibilist reductions to free will are subtle; saying we are able to do otherwise, meaning we are able to do otherwise if we want to. Likewise, Open Theists may have subtle and dangerous additions to free will.