Is it ethical to submit to same different URL on the same domain?

In your other copy of this discussion you asked if it's ethical for SEO. Again, it makes no difference: most search engines completely ignore the "keywords" meta tag these days (because in the past it's been stuffed with useless or inappropriate content) and work out your keywords by analysing the page content itself. So even if you submit multiple pages (with different keywords - though I've never seen a search engine submission page that asked for those) - the indexing process will take care of everything in the same way it does for everyone. No difference: you're just wasting effort by submitting multiple URLs (unless they're not interlinked at all, of course, then it's like submitting multiple sites).

And the search engines might get irritated if he do that repeatedly. It's like submitting your index repeatedly, because even if he thinks what he's submitting are inner pages, the index is still always there, included. So, when not sure if it is okay, better don't do it.