I am not quite sure how this works, and maybe more knowledgeable readers can help with more accurate details. If an Israeli grows up abroad, let's say, for example, that a couple decides to move abroad and raise their child there. Technically, when that child turns 18 he is supposed to join the IDF draft just like any other Israeli.

Some people want to. They are raised with motivation to serving in the IDF, and at 18 they join, as they always wanted and planned to.

Others, who perhaps see less of a value in serving, especially since they do not live in Israel, or maybe they give priority to other plans, or maybe they don't want to serve for a variety of reasons, can find a way to avoid it by not stepping foot in Israel.

Back in my yeshiva days there were always some guys in yeshiva who came to Israel a bit older because of "army problems". Some had to make special arrangements to come to Israel and not be taken to the army. There were even some who took the drastic step of renouncing their citizenship.

The common denominator was that they did not really have to deal with the issue, if they did not want to, and I may be wrong about this, until they planned to travel to Israel.

Interestingly, a young Israeli has made the news on ESPN for having to give up his college basketball career in the US due to turning 18. He now has to give it up and join the IDF. After working out a brief postponement, it is now time for Tom Maayan to quit his basketball team and join the IDF.

I do not know why he could not avoid it and delay it simply by not planning any trips to Israel, and then joining the IDF at a later time. Maybe he wanted to, but it seemed he really wanted to continue playing basketball but had to stop.

From ESPN:

Israel is one such place, and far more famous for it than the Swiss. At the age of 18, Israeli citizens are required to report for Israeli Defense Forces enlistment and training. Males are required to serve for three years; females for two. As the Star-Ledger's Brendan Prunty reports, one of those males is Seton Hall guard Tom Maayan, whose redeployment to the IDF cut short his basketball career in rather sudden and emotional fashion Tuesday night.
Why so sudden? Maayan was originally ordered into basic training this summer. But through "lobbying and politicking with the Israeli government," Prunty writes, SHU and Maayan's guardian were able to get an exemption to play for the Pirates this season. In November, that exemption was shortened to 120 days. Seton Hall kept up its push, but the reprieve officially ended Tuesday night after the Pirates' win over NJIT. Coach Kevin Willard made the news public after informing an "emotional" locker room.
"I think the yo-yoing was tough for everybody," Willard said after in the hallway of the Prudential Center. "It was tough for him -- those are his teammates, his family. His extended family. Leaving them wasn't easy. It wasn't easy last time and it wasn't easy this time, either. But it is what it is."
"We knew about it, but it was definitely tough," [teammate Sterling] Gibbs said. "Tommy's like a brother to us. It's like losing one of your brothers."

Serve well, Tom. Best of luck. You probably would have liked to earn a mention on ESPN for a great game and great skills. You earned it for other reasons, but at least you earned it.