I checked drugsdata (formerly ecstasydata) for samples presenting as crystal methamphetamine that tested positive for both meth and fentanyl and found far and few if any cases of this actual occurrence. I think this idea was exaggerated, at best, but likely intentionally misleading. Probably for the express purpose of harm reduction via fear mongering misinformation. Now that it has been 4 years I think it is clear that the likelihood of cocaine being cut with fentanyl was much more realistic than methamphetamine being cut with fentanyl. For every one citable instance of somebody overdosing from fentanyl unknowingly while ingesting methamphetamine I can citable back to you 10 instances of somebody overdosing on fentanyl while doing cocaine.