I would like to think the output is diode protected and thus the device wont resent any load when not powered.. But alas that is how **I** would build them (in fact I do build power supplies)
I know Progressive Dynamics the wizard is still on line and the fan, far as I know those are the only loads (The Wiz is basically a voltmeter load, not much).
Can't talk about others
IF you can adjust the output voltage of that Meanwell... I'd put a heavy duty diode in the line (Say a set or half set of alternator diodes with heat sinc and fan, hook the fan to the Meanwell side) And increase the voltage by the amount indicated.. or a diode isolator and again increase the outut by the diode drop.