not really, when you write a script to add instances, i'm sure you would
put a check on the no. of instances, i.e. at max 10 for eg.similarly,
when the delete button is clicked, it would calculare the no. of
instances every time before deleting.once the no. of instances is one ,
you can ask the script to hide the field with the caption.you can
definitely find samples for this , if not let me know, i will make a
quick one