Unfortunately I think you're being a little too optimistic. The reality I've seen is that GET is used for all sorts of things, including state changes and irreversible consequences.
Analytics could check for useragent (and probably already does), but it just introduces a lot of noise.
Plus the other concern is that it'd be a huge privacy issue to have analytics being triggered just by performing related searches.
That it shouldn't be used on a search engine's results page.
Preload within a domain is reasonable. Preload across domains is, imo, a security concern, but maybe acceptable if the domains are trusted. Preloading untrusted, unknown content is a terrible idea.
