本页为相关案例科普与教学材料，供理解加拿大（含BC）子女抚养费变更中的“有效通知”与回溯期规则。非法律建议。
Educational material on the Supreme Court of Canada decision governing retroactive decreases in child support and rescission of arrears. Not legal advice.
Citation: Colucci v. Colucci, 2021 SCC 24
Court: Supreme Court of Canada
Date: June 4, 2021
Issue: Framework for a payor parent’s application under s. 17 of the Divorce Act to retroactively decrease child support or rescind arrears.
案号： Colucci v. Colucci, 2021 SCC 24
法院： 加拿大最高法院
日期： 2021年6月4日
核心问题： 支付方根据《离婚法》第17条申请追溯减少子女抚养费或减免欠款时的适用框架。
1. Effective Notice is Critical
To preserve a retroactive decrease period, the payor must give the recipient effective notice of the material change in income, accompanied by sufficient reliable financial disclosure. Mere verbal statement without proof is not enough.
1. 有效通知至关重要
要保住追溯减少期，支付方必须向收款方发出有效通知，并附上充分可靠的财务披露。仅口头说明而无证据不够。
2. Presumptive Retroactive Period
Once a material change is established, there is a presumption in favour of retroactivity back to the date of effective notice, up to three years before the formal application to vary.
2. 推定回溯期
一旦证明存在重大情况变化，即推定可回溯至有效通知之日，但最长不超过正式变更申请前三年。
3. Colucci Caution
In Colucci, the father failed to provide adequate disclosure and evidence of income drop. The Court held he had not given effective notice, and his application for retroactive decrease was denied. Blameworthy conduct (non-payment, lack of disclosure) weighed heavily against him.
3. Colucci 案警示
在 Colucci 案中，父亲未提供充分的收入下降证据与披露，法院认定其未发出有效通知，追溯减少申请被驳回。未付款、不披露等应受责备行为对其不利。
Practical Implication for BC Variation:
To preserve any possible retroactive period in a British Columbia variation application, early written notice by counsel together with full financial disclosure is essential. Delay or inadequate disclosure can forfeit the three-year window, as illustrated by Colucci.
对BC变更申请的实务启示：
要在不列颠哥伦比亚省变更申请中保住可能的回溯期，必须尽早由律师发出书面通知并充分披露财务。拖延或不充分披露可能导致丧失三年窗口，正如 Colucci 案所示。