
Filing this issue to track a question/comment that was raised by @ywangd  here https://github.com/elastic/elasticsearch/pull/98309#discussion_r1294115440

One question I do have is why we chose to [execute the LookupRequest with the enrich origin](https://github.com/elastic/elasticsearch/blob/2e4440ff1c0decf79f8a40688566411f7d518aa7/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/enrich/EnrichLookupService.java#L141C2-L141C2). It means the following query works when the user has access to only the playlist index without access to either the songs enrich policy or its associated index.

```
FROM playlist | ENRICH songs ON song_id
```

It feels a bit weird to me that we have no control on who can use what enrich process. That said, we don't have a good story around enrich and ingest pipeline either, i.e. we have no control over who can use what pipeline where a pipeline can contain an enrich processor. There have been quite a few complaints from users and we have an https://github.com/elastic/elasticsearch/issues/57586 for it. I wonder whether we should not repeat the problem here with ES|QL. On the surface, it might be easier to tackle compared to ingest pipelines since ES|QL is read-only and has no "bulk" operations. What do you think?
x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/optimizer/LogicalPlanOptimizer.java
new BooleanSimplification(),
            new LiteralsOnTheRight(),
            new BinaryComparisonSimplification(),
            
            new PropagateEquals(),
            new PropagateNullable(),
            new BooleanFunctionEqualsElimination(),
            new CombineDisjunctionsToIn(),
            new SimplifyComparisonsArithmetics(EsqlDataTypes::areCompatible),
            
            new PruneFilters(),
            new PruneColumns(),
            new PruneLiteralsInOrderBy(),
            new PushDownAndCombineLimits(),
            new PushDownAndCombineFilters(),
            new PushDownEval(),
            new PushDownRegexExtract(),
            new PushDownEnrich(),
            new PushDownAndCombineOrderBy(),
            new PruneOrderByBeforeStats(),
            new PruneRedundantSortClauses()
        );
        var skip = new Batch<>("Skip Compute", new SkipQueryOnLimitZero());
        var cleanup = new Batch<>("Clean Up", new ReplaceLimitAndSortAsTopN());
        var label = new Batch<>("Set as Optimized", Limiter.ONCE, new SetAsOptimized());
        return asList(substitutions, operators, skip, cleanup, label);
    }
    
    static class SubstituteSurrogates extends OptimizerRules.OptimizerRule<Aggregate> {