In British Columbia, some testators left little for some of their independent adult children, while leaving most of their assets to their other children. In many of those cases, the courts granted the wills variation claims of disgruntled beneficiaries, and while doing so, the courts are required to make the distribution "adequate, just and equitable" under BC law. This can result in a distribution that strongly contradicts the intentions of those testators. A famous example of those cases is Tataryn v. Tataryn Estate,  2 S.C.R. 807.
In other provinces, Ontario for example, testamentary freedom is upheld more strongly. Under Ontario law, if a bequest is unambiguous, unequivocal, and unconditional, courts will not scrutinize it to the extent under BC law. In Spence v. BMO Trust Company, 2016 ONCA 196, the judge even says that a testator does not even need to specify a reason for testamentary dispositions, and "the privacy of those reasons is inherent in the principle of testamentary freedom."
If the testators in the BC cases had inserted a choice of law clause specifying that the laws of another province (such as Ontario) would govern, would it have helped to achieve their desired testamentary dispositions?