“People feel obligated to give a tzdekah who calls them up, no matter what the cause….”
People may feel obligated to do lots of questionable stuff but its borderline meshugah to give a credit card donation to some schneurer calling blind over the phone with a “heimeshe accent” claiming to be collecting for yesomim on behalf of some modsos you’ve never heard and likely doesn’t exist. Even if the guy shows up at your doorsteop motzi shabbos with a laminated “hechsher letter” from a rav you’ve heard of, I would still not give a dime without doing more checking since such letters have been known to be copied and forged. Best to give a check/credit card donation directly to through your shul, beis medrash or through someone you’ve confirmed is reputable. Obviously, not a concern when some of the local yeshiva boys/girls come around with a pushka asking for a donation but once you get into any serious dollars, the answer should generally be NO w/o further due dilligence.