People respond to incentives. If you make something harder, people will do less of it.
New barriers include: the actual work of moving money around to and from friends and family and directing trades, counterparty risks in doing so (e.g. sibling dies and leaves money to someone else or takes the money and runs), tax complications, or reputational risk if found to be violating "spirit of the law" that might harm election odds. There are surely more frictions and barriers like these that I'm not capturing.
New barriers include: the actual work of moving money around to and from friends and family and directing trades, counterparty risks in doing so (e.g. sibling dies and leaves money to someone else or takes the money and runs), tax complications, or reputational risk if found to be violating "spirit of the law" that might harm election odds. There are surely more frictions and barriers like these that I'm not capturing.