This as already been discussed in the past, (https://hibernate.atlassian.net/browse/ANN-127). Since the support of JodaTime classes, it really makes sens to be able to specify if the annotation is inclusive/exclusive of the current instant/time/date...
For instants it may not be soooo useful, but this is really helpful for non instant date descriptions like LocalDate (but could lead to timezone problems btw...).
My simple usecase is that I have a form with a begin and a end. Both fields are LocalDate with no time. End must be after begin, and end must be either today or in the future. If we are 2013-09-10, the user must be able to select begin=2013-09-10 and end=2013-09-10 for example.
With the current exclusive annotations this is not possible and lead to the creation of a "FutureIncludingNowValidatorForReadablePartial" or a validation through a method.
I don't really know how this behavior can be modified since it's in the javax.validation, perhaps the next version of the specification could be updated?