In Henderson v. Slavkin et al., 2022 ONSC 2964 Justice Carole Brown dealt with the legality of an ESA Termination Clause. The actual termination clause itself was found to be OK, but both the confidentiality clause and the conflict of interest clause had the following sentence.
A "termination clause" is a type of contractual term which specifies entitlements owed to a worker at the end of their employment. They come in many different shapes and sizes. Whatever the construction, the usual motivation for employers in drafting termination clauses is to control costs and provide for certainty at the end of the employment relationship.
As an employer, you want to control when your employees do and do not take vacation time. Can you do this? The answer, for all jurisdictions in Canada, is yes, though this employer discretion may be restricted in some jurisdictions.