In America it would be fine, but I assume things are much different in TLV
TLV can be a pain, because you're not only going through security, but also going through passport control and effectively leaving country. Leaving airport after that means you have to go through immigration to reenter country, which requires assistance from security and airport staff. They can get fairly annoyed and suspicious, so make sure you have a good story about why you're not flying (I wouldn't tell them you booked refundable to accompany someone to gate - they probably won't be too amused). They will likely double check to verify that you didn't check and bags and your ticket is legitimate, nobody got on plane in your place, and was actually offloaded and cancelled. You can't just cancel ticket and walk out of airport the way you can in USA.