Can we register prefixes for known brand names?

WebMD, healthline, Google, Bing are big brands. Can we register (and is it allowed) to prefix them, e.g. ZeroWebMD or GogoGoogle? Do you think other than bots someone does read text at Google/Bing?

In some markets you're sure to get the copyright bots on your case. Maybe less so with certain tlds, eg .ru, .su
It's usually not worth it.