Depends on what you mean by "intercepting". You can do that now on Google AdWords if you're will to out spend anyone else for those keywords like 'Android'. In that instance, all it means is that an ad for your product appears when someone searches your rival. In fact, I'm pretty sure this SOP for marketing teams.

If you mean replace any relevant search results for 'Android' with 'iPhone 12' and/or 'iOS 14', then yeah, that would be pretty egregious. However, I can't see that actually happening for a couple of reasons. 1) it would be so obvious it was happening that there's no denying it, 2) it would be so damaging that it would be a service killer as it's all anyone would talk about and never trust it