Alas, BMW buyers often cannot opt out of keyless entry, because for some models BMW includes it in popular bundled packages, such that it's impossible for the consumer to avoid buying it without losing other worthwhile features. This consumer-unfriendly bundling results in BMW buyers often facing what can only be described as ridiculous choices ("which one do I want: a rear-view camera that reduces the risk of accide…
It's not keyless entry, it's the electronic keys used for push-to-start (which is also an unavoidable option, but it's one I like).
FWIW, I know about this firsthand because I bought a new BMW last year and I was adamant about not having the "keyless entry" feature -- for security reasons. The BMW salesperson acted like I was a bit crazy.