What is the impact of a party’s email to the opposing party of a parenting motion for custody of the children?

The Ontario Court of Appeal has ruled that the utmost caution must be used before striking a party’s pleading as it relates to parenting issues because a full evidentiary record that includes the participation of both parents is generally required for the court to make a custody decision in the best interests of the children. The decision in Burke v. Poitras, 2018 ONCA 1025, is one example. My view is that this principle should also be considered here. It supports the general policy of the court giving preference to deciding cases on their merits rather than by default. Ultimately, it is in the best interests of the children for the court to hear from both parents and determine the impact of the respondent’s actions on the parenting issues on a full evidentiary record, including her concerning and highly offensive emails to the applicant. What is the potential prejudice to the moving party should the motion be dismissed, and the potential prejudice to the responding party should the motion be allowed?