  At the "New Horizons in Globular Cluster Astronomy" conference (Padova, June
2002), two members of the VLT globular cluster team presented different views
on the importance of heavy-element sedimentation in Population II stars: "The
lack of evidence for depletion of Fe and Li in the atmospheres of globular
cluster subgiants led some people to suspect that, for unknown reasons,
Population II stars are not affected by this mechanism." (Castellani 2003) and
"There should be some mechanism that prevents sedimentation." (Gratton 2003).
  In this review, I will argue that the scepticism behind both these statements
is justified. We recently revisited the results on sedimentation in NGC 6397
stars presented by Gratton et al. (2001) using higher-quality VLT/FLAMES-UVES
data (Korn et al. 2006, 2007). Element-specific abundance trends were
identified which agree with atomic-diffusion predictions, if turbulent mixing
below the convective envelope is accounted for in a parametrized way. Have we
thus detected signatures of Atomic Diffusion in Old Stars (ADiOS)? Or are these
trends mere artefacts of Conspiring Inaccuracies in Abundance Observations
(CIAO)?
