This kind of widget could not effect your site ranking. It may has some exception - If your site has a little to no unique content but has a full of widget / affiliate links / PPC ads. Your site would be defined as "Thin Affiliate" site by Google and caused for dropped in ranking.
I was having my site in Top 10 for a few low competitive niche, was getting 200-300 UV daily and then I decided to put CPALead on my website and after 3-4 weeks when I check my website again it was no where on Top 1000 on Google.
A big YES First of all, CPALead javascript is not just a widget, it provides a dominating low quality content to your website and the actual content is hidden behind the javascript code. So no relevent content exist anymore and guess what when google crawler sees just chunks of javascripts with links to offer websites, which are generally spam and virus inducing, what do you expect from it ? I guess you know the answer.
@psharma seems you dont really get the point of cpaleads widget. it does not alter your sites code and content. its just one line of javascript that calls code from cpalead server which then overlays your site by CSS. google still reads and indexes your whole site.
Are not you talking about the areas of your website restricted by CPAleads surveys? if no, then my answer would be different. : ) hehe