Wiring Single-Cell Lipo Chargers in Series

Can you wire the "load" outputs on two single-cell lipo chargers (e.g. this or this or this) in series, to get a larger voltage that's still safe and easy to recharge?

I understand the dangers of wiring and charging the lipo batteries themselves in series. If the cells become unbalanced, then one of the cells could potentially explode or burst into flame. This is probably why so few online stores sell multi-cell chargers for embedded applications...

However, is there still a danger will when it's chargers, and not the batteries, that are wired in series? Shouldn't the voltage regulators on these chargers, and the separate charging circuitry, effectively balance the cells when charging and discharging?

This question is related to an earlier question.

You can only attempt that if the chargers have floating outputs - in that case you have two separate circuits
(that happen to share one point in common).

Try plugging both chargers in, but not connected to batteries. Measure the voltage from - of one charger
to + of the other, and then vice-versa (make no other connections between them!!). If the outputs are floating
both readings should be zero (the internal resistance of the multimeter is enough to bring them to the same potential.

The downside to this scheme is that you won't balance the cells accurately if the two chargers are slightly
different, and you won't guarantee the same amount of charge passes through each one - meaning balancing
is more important. However if the chargers are the same model and if a multimeter shows they balance the
voltages well, it ought to be workable - but you will have to always do a full balancing charge, not just a fast-charge,
otherwise differences in the cells could imbalance them (which then causes one to reverse during discharge, ruining it).