I haven't heard too many concerns about the SP101 having flame-cutting problems.
Generally speaking, it's with guys shooting very hot magnum loads over an extended period of time. While that is possible, in theory, with the SP101, it would not be a very fun test platform to use due to its short barrel and light weight.
Flame cutting is the reason S&W installs blast shields on their space-age revolver frames. In order to avoid it, shoot less powerful ammunition. Some have suggested that never cleaning the area above the forcing cone can retard strap cutting, as the built-up carbon acts as a shield.
I would not be concerned about it with an SP101. If you were buying a Ruger Blackhawk or Dan Wesson in .357 Maximum or .357 Supermag, it would be something to check for.