When I file my taxes, I take every deduction that I am allowed to, but I would never take deductions that I am not entitled to (or ch”v misreport my income in any way). Similarly, there is nothing wrong with taking benefits that the law allows. But there is everything wrong with playing games (e.g. cash under the table, hiding assets, etc) and then claiming benefits.
Unfortunately, these gneivas are sometimes done by individuals in all segments of our community. I understand the yetzer hara to do it. But it is completely wrong, legally, morally, and halachically.
(As an aside, it’s really stomach churning to hear the same person argue that every chumra must be followed in bein adom l’makom, but search for every kula when it comes to the possibility or safek (or even not so safek) gneiva. Some people call it clever. Perhaps a few gedarim should be enacted here too.)