In the same town, I have a client who had a competitor that went
out of business a few months ago.  The competitor's defunct
website is still ranking higher than the client's website in
search results for the same keywords.  The client wanted to try
to purchase their competitor's domain name and just use a 301
redirect to point to their website.  The competitor's domain
name is splashed all over the place--on social media and
legitimate directory pages (like yelp and a few locally-driven
business listings).  Is this a legitimate technique, or will it
hurt rankings in the long run?