I bought my RS March 30th, 2017, had zero trouble attending August 2, 2018. I received my welcome kit after all 2017 spots were full. I emailed RSAA, they extended my deadline until the end of 2018. I was advised to sign up immediately when registration for 2018 opened.
The people that I feel for are the folks that bought a new RS after all of the final spots were filled for 2019.