Product unrestricted modifier security?

Hi. I'm adding a number of products in romancart which will be displayed on my website with different buying options, including a free format text box. I've added the text box on my roman cart product using an unrestricted modifier. Does anyone know if there is anyway to add security to that field, i.e. so that it pops up a captcha box? I'm generating the html code for each product from roman cart. Maybe there's some code I can insert to add this?? Thanks!