As long as both parishes agree, why say it’s not appropriate? Nobody would suggest that it’s inappropriate for the bride or groom to return to one or the other of their childhood parishes to be married, even if they live elsewhere, so why should opting for Hawaii instead make it inappropriate as long as the proper paperwork is done.
Because Canon Law says the proper place is the Groom’s parish, or the Bride’s.
Can. 1071 §1. Except in a case of necessity, a person is not to assist without the permission of the local ordinary at:
1/ a marriage of transients;
2/ a marriage which cannot be recognized or celebrated according to the norm of civil law;
3/ a marriage of a person who is bound by natural obligations toward another party or children arising from a previous union;
4/ a marriage of a person who has notoriously rejected the Catholic faith;
5/ a marriage of a person who is under a censure;
6/ a marriage of a minor child when the parents are unaware or reasonably opposed;
7/ a marriage to be entered into through a proxy as mentioned in ⇒ can. 1105.
§2. The local ordinary is not to grant permission to assist at the marriage of a person who has notoriously rejected the Catholic faith unless the norms mentioned in ⇒ can. 1125 have been observed with necessary adaptation.
Can. 1115 Marriages are to be celebrated in a parish where either of the contracting parties has a domicile, quasidomicile, or month long residence or, if it concerns transients, in the parish where they actually reside. With the permission of the proper ordinary or proper pastor, marriages can be celebrated elsewhere.
Underlining & emphasis mine.
This has as much to do with proving the requirements of preparation as it does the communal and public aspects of marriage.
Marriage is a PUBLIC sacrament. It’s the only sacrament bound also by civil laws. It requires, except in severe and dire cases, public recording. (Yes, there’s a whole section on secret marriages… but it’s also pretty clear that they are not to be used except in really odd cases.)
Further, in the Eastern Churches, the approach to the “adult” sacraments is very different from the Roman Church, but it underscores what is most important:
For marriages, they are celebrated outside the Divine Liturgy; the celebration traditionally begins in the home of each, with a priest or deacon going and verifying that both parties, separately, agree to the marriage, and have the support of the families. Then they proceed to the parish, give their consent outside, and then proceed to enter, and are bound together by the priest, and crowned by the priest as a new adam and new eve. Traditionally, weddings are done on saturday mornings. The couple then usually receives honored place the next morning by being communed at the same time at the start of communion, to give public witness to what was done.
Ordinations and Solemn Professions (of Vows or Promises) in the East are done DURING divine worship services only, and are ordinations supposed to be scheduled in the home parish on a sunday… given that the east usually restricts to one liturgy per day per altar, this means at the regular sunday liturgy. The Catholic East is more lax about the one per day than the Orthodox East…