Sitting on the board of a 3 people outfit is not the same as having few shares of McDonald's. If the OP is planning to have a GC in the future, he/she needs to understand that USCIS looks into "intent" to figure out things, such as coming to US with a nonimmigrant visa and applying for AOS next day shows "intent" that you breach the terms of your nonimmigrant "intent". So if you are "silent" shareholder in a small LLC and "volunteer" a lot, USCIS may see this as intentional unauthorized employment. Just my 2 cents.