Written instructions in every Israeli embassy worldwide advise individuals to conceal their Israeli identity, providing many practical details on how to do so. I can guarantee that, as an experiment, if you approach Israeli people abroad and ask if they are Israeli, at least 9 out of 10 will deny it. Most probably - all 10. This is why I find the warning discussed in this thread to be quite unusual, as if UK foreign office would advise all their citizens not to put their arms on open fire.