How should region-aware public web data be evaluated in a multimodal Gemini application?

I am designing a multimodal application that uses permitted public web data as one input source, and I am trying to understand how other teams evaluate regional variation.

The same page, image, advertisement, or search result can change by country or city. For a Gemini-based workflow, should these be treated as separate evaluation slices, or should the application normalize the differences before sending the data to the model?

The checks I am considering are:

  • requested versus observed location
  • language and local formatting
  • image-text consistency
  • freshness of the source
  • answer quality across regional variants
  • behavior when a region-specific field is missing

One possible design is to keep a global benchmark and add separate regional slices. Another is to normalize the source data first and evaluate only the normalized representation.

How are other teams handling this in production? I would especially appreciate examples of evaluation schemas, metadata fields, or failure cases that are easy to miss when building a Gemini-based multimodal application.

The collection layer follows the rules of the public sources and uses location-aware network access only where the task requires it.