Google is removing Checkout badges from Adwords advertisements (as of June 2011) for google.com and google.co.uk. The change affects both types--standard and promotional badges (for-profit and non-profit eCommerce).
They will continue to be displayed in Google product search pages. Badges were first on the scene in 2006.
Source:
eCommerceCircle
Google Help: https://checkout.google.com/support/sell/bin/answer.py?answer=1323905