Good question.
Any kind of pressure is not a wise solution, especially to yours down-line.
You can simply explain them the benefits of Standing Order:
With low budget of 1 TC SO could be enough for starting point...
But after 2 or 3 months you can explain to yours affiliates that it is quite obvious that SO with 1500 VersaPoints makes them EA every month.
So, if they want to make progress and bigger income, they should have their SO every month.
Best Regards