We use the presence of executionStats docsExamined field to detect whether SBE or classic is being used: https://github.com/10gen/mongo/blob/1fb5ac482b2f857305f3224bd7e99d071fff1e6e/jstests/libs/clustered_collections/clustered_collection_bounded_scan_common.js#L46-L50

However when sharding is enabled, the docsExamined field shows up underneath the shard results rather than at the top level. We should check in both places.