I doubt if this will ever be a widespread issue, its not like its even a new problem, just a bit more streamlined. Its always the fringe that gets noticed, and the guy who saves $50-$100 on his $1000 purchase will feel the pinch when something goes wrong and he has to either wait 2 weeks for service or repair, versus calling his local store and have a replacement tech come right out.
Not a new problem for B&M for sure... but as stated, it may get us flat-rate Internet Sales Tax discussion going again. (to help level the playing field for local B&M)
I used to work at a place that was often price-shopped against online places. When someone mentioned they saw it cheaper online, we directed them to a terminal, so they could place their order. Minimize the loss, move on. If they had any additional questions about the product, we told them to feel free to ask online. 90% of people know the value in the brick and mortar when you explain the differences. The other 10% are price shoppers and regardless of what you do, will ALWAYS buy the cheapest price!