My wife sent a package today (Wed) to Canada from Israel using 5 day express Israeli mail service. The package was sent to family who are secular Jews. It is very possible the package could arrive on the second day of Shavuos. The Canadian postal service does not work on “weekends” so it may that the package cannot arrive on Shabbos or the first day of Shavuos. However, even this I am unsure as perhaps the package could be delivered in Canada through another company.
It is possible the package could arrive before Shabbos (5 days is the maximum they claim it takes to deliver).
It is also possible the package could only be delivered later after Yom Tov
Are we obligated to contact the secular family members and request from them not to receive the package on Shabbos or Yom Tov. This would be uncomfortable to do, but possible.
If you could contact me through email it would be a big help.
Thank you and all the best.
Don’t be too concerned about it. Unfortunately the Postal service is not living up the time schedule that they claim, and it most probably will not be delivered on Yom Tov. If it gets there on Yom Tov I would be very surprised.