It's also worth noting that most digital designs only live 1-2 years before being redesigned. So, even though this goes against what I said earlier, sometimes current trends are good, as long as you are also attempting to forecast the next two years.

Unfortunately sometimes a project is a project and you simply do it to get paid :( but I still suggest doing whatever you can to help educate the client and properly provide a solid solution for the problem at hand. Even showing other, current designs as a comparison to what the client is referencing (hint: you don't have to show other sites/apps in the same field, for example banks and universities always have sucky design, so if designing for a bank why would you inspect what other banks are doing? Check out and reference similar industries that are doing it well!)

Good luck!