Assuming the labels are just static text you can't hide them directly. What
you can do, though, is place white fields on top of them and then show
those fields when you want to hide the text underneath, and hide them when
you want the text to be visible.
Many thanks Gilad, yep they are static text, your solution sounds viable.
For anyone who may benefit - this is what I did.
In checkbox properties:
Select Trigger: Mouse Up
Here is the JS:
// Show/hide alternate shipping address text fields
var nHide = event.target.isBoxChecked(0)?display.visible:display.hidden;
this.getField("SHIPPING ADDRESS").display = nHide;
this.getField("CITY_2").display = nHide;
this.getField("STATE / PROVINCE_2").display = nHide;
// Show/hide alternate shipping address text field label overlays
this.getField("Overlay_1").display = event.target.value == "Off"? display.visible: display.hidden;
this.getField("Overlay_2").display = event.target.value == "Off"? display.visible: display.hidden;
this.getField("Overlay_3").display = event.target.value == "Off"? display.visible: display.hidden;
So the overlay simply refers to three text fields I added to the PDF form, which cover the labels for the three text fields that are hidden/visible for use as an alternate shipping address. The properties of these overlay text fields in the Appearance tab ensure the border color and fill color, (there is no text), match my document's background. Then, under the General tab, provide a name (i.e. Overlay_1, etc.), no tooltip needed, and then check Read Only. This last bit will ensure that when the user selects Highlight Existing Fields (upper right corner in green bar), these three overlay fields don't appear in the document (they just look strange and confusing if they do).