They aren't that fragile, at least properly made ones. Your CAT II/300 test requires clamping 100+ amps, the BBQ lighter is just a bit of ESD. The two are not similar events in any way.
It's that I want hard proof this very expensive DMM is impulse-tested for differential and common-mode transients to some value say at least 1,500V. Not someone's "opinion", not "designed to" (engineers with good intentions) or "meets" (who says?) or "CE" sticker or "spec'd to" etc.
An ongoing problem with multimeters is fake or misleading 61010 approvals.
"Cat. II" on the front panel means nothing - was it evaluated to 61010-1, 61010-2-033 ? And even then, a certification agency can make mistakes. Remember the Keysight 600V fiasco it was just terrible.
For a bench DMM it's not safety approvals so much as a guarantee it can take a BBQ lighter so I'm not looking at a massive repair cost due to normal use.
i.e. DMM6500 has Intertek approval ETL marking for 61010 but Keithley 2000, 2001, 2002 has nothing- which is probably why they frequently get damaged.
61010-1 is "for electrical equipment for measurement, control, and laboratory use –"
-2-033 is for "Particular requirements for hand-held multimeters and other hand-held meters, for domestic and professional use, capable of measuring mains voltage"
"It's that I want hard proof ..."
I doubt you would ever find it. BBQ starters will very a LOT. I have characterized the one I use, presented the data for it and have shown how it compares with IEC waveform. I would expect completely different results if I went to the hardware store and bought a new one. BBQ starters are going to output several KV, far beyond the 1.5KV you mention. Their rise times can be well under 1ns and pulse width is going to be <100ns. I think the one I used can put out close to 5A peak, far from what the standards call for.
If say you pick some magic number (1.5K) as your criteria. Let's not focus on how you came up with it but assume you know this is what you require. What does the waveform look like? What's the voltage rise time into and open circuit? What's it's decay look like? What's the current look like into a short? .... These are the questions I was pondering when trying to come up with a way to benchmark handheld meter. Being unable to locate any sort of existing standards, my proposal was to somewhat follow the surge open circuit voltage waveform, greatly limit the energy available and not superimpose it onto the line.
If I applied this type of waveform at 8KV peak to your favorite bench meter and it survived, it may give you a great feeling of comfort but it will not mean you can connect the same meter to 2KVDC or a MOT. Hard proof requires hard requirements. From there it's possible you could have these tests performed at some outside lab. The cost may far exceed the cost of the meter but you would have your hard proof.
A beginner may suggest if a meter survives +/-1.5KV DC, it would handle every transient up to that. At one time I made an attempt to provide some insight on how to harden a cheap UNI-T UT-61E and show how a fast edge can be a problem. Sadly, most of the people who watched the video didn't seem to care about the approach to solving this sort of problem. The wiki experts just need to know how to mod their cheap meters.
I just finished the chapter on colleges. An excellent book.
https://www.amazon.com/Death-Expertise-Campaign-Established-Knowledge/dp/0190469412