Add this phrase from economics to your vocabularies to describe the "other" studies where proxies with known HS shapes like bristlecones and Yamal are used time after time. Here’s a website with some links. They cite Sullivan, Timmermann and White (1999) and White (2000) for the following definition:
"Data-snooping occurs when a given set of data is used more than once for purposes of inference or model selection."
The topic is actively being researched in econometrics and the methods need to be applied to multiproxy studies.