I'm in no way the battery police, and others here have aptly expressed concern, but here's my thoughts:
Someone on here (ECF) uses trustfire batteries, and has for a year or more, without issue. If I recall correctly, he is building sub ohm but only down to like .4 or so.. could be wrong on that.
Many build super low (or stupid low, depending on your understanding of safety) on batteries that simply can't handle the load. They have vented batteries, but claim that its not dangerous: the mod gets hot, and the battery vents, nothing crazy. Just because IMR batteries are "safe chemistry" doesn't mean that they cannot violently vent, just that they are less likely too, personally I see no need to push the envelope. Building low on an ICR battery is just asking for a trip to the hospital IMO.
Just because something hasn't happened, doesn't mean it won't. Just because someone hasn't gotten into an accident while driving drunk doesn't mean they won't, and it certainly doesn't make impaired driving a good idea.
As I recall, EFest purple 35amp batteries are rewrapped LG HE2s. Generally the companies that buy batteries to rewrap get the lower quality batteries, LG saving the best batteries from the run for themselves. I don't remember where I saw that, but it's probably worth looking into if you are going to exceed your batteries continuous amp rating...
As a personal rule I try to stay under the continuous amp rating. That gives me more vape time on the battery, and stresses the cells less so they will likely withstand more charge cycles. I can get satisfying clouds on a .3 ohm build with 24ga... but generally I vape for flavor with single coil 1.2-1.6 ohm 28ga builds - depending on the atty.