Similar psychology:
Forcing users through steps they didn't choose could trigger reactance and an increase in churn, as people simply don't want to do that thing.
Steps that appear to force users into inviting friends may provoke reactance, making them less likely to ever genuinely recommend the product.
Keeping steps optional and skippable might reduce the discomfort and frustration users feel when reactance kicks in against forced behaviours.
Letting users click around at their own will, rather than forcing a set path, could avoid reactance and increase how much they enjoy the product.