That should already be the case, but seams to be some sort of odd issue with jQuery Validate not becoming active until the form is in use. You have to add text, select a different input, now remove your text, and then select a different input and it'll throw the required error. Same behavior seen in CB can be seen on jQuery Validate demo page below.
jqueryvalidation.org/files/demo/
Not sure what the cause is or solution, but will check their github to see if it has been reported yet.