Why would that be any different ? If you hold shares for 10 years you are surely not a professional trader. A professional trader in their mind is someone doing day trading, playing with leverage and derivatives and whose income rely on his trading gains. If your profile is not the latter you have nothing to worry about.
Also keep in mind that you are not required to send your individual trades with the tax return, only the value of your holdings at end of year and any dividend or revenue from a self reinvesting fund (check the ICTax website). So again they will only start an inquiry on you if you post an increase in taxable wealth that cannot be justified by your work income. Each year around the same period the forum sees an influx of people asking questions around that topic when we are still to see someone actually testify here that he was classified as a professional trader. I remember a press article saying that per year they had less than 10 people in the whole Zurich canton to be investigated for this.
Final point, the Swiss tax authority is not the IRS, only if you commit fraud will you be prosecuted, if you forget something in your return and they realize it you only risk paying back what you owe with some penalty but you will not go to prison. Really, this topic should not prevent you from sleeping.