You can use browser extensions (e.g. User-Agent Switcher for Firefox) to manipulate the user agent string presented to the remote site. However, if a search engine can see the answers, so can anyone else who goes through these motions. Experts-Exchange tried this, and failed.
Making answers visible to search engines, but trying to hide them from people browsing the site unless they sign up is a UI dark pattern, and I strongly recommend people stay away from this garbage.