I am on a school trip to Israel and one school the rules is that you are not allowed to drink alcohol. When I stayed with another family during my time there, we went to their grandparents house for a shabbat dinner. They offered me a glass of wine during the kiddush. Should I take it not to embarrass the family and disregarded the rule or should I not take it and follow the rules but I may embarrass them?
You can drink the glass of Kiddush wine.
This does not involve disregarding the rule, but only interpreting it.
It stands to reason that the prohibition against alcohol was not meant in the religious or “ritual” context of Kiddush for the Shabbat meal, but rather in the context of drinking alcohol as young people (especially) are prone to do outside the Kiddush / religious ritual framework – which is known to lead to unfortunate consequences.
Therefore, I don’t see any problem in drinking the small amount you are offered.