In reply to Mattdixclimb: Speaking as someone who has worked in substance use research for the past 9 years..I can absolutely assure you cannabis has no performance-enhancing properties.
And image and performance-enhancing drugs are my particular area of research interest...although I have done work around cannabis use too.
As for the cheating debate; cheating implies rules. You can only cheat rules....if you're not climbing competitively..how are you cheating? What do you lose from the experience when climbing using performance enhancers that you get when you climb without them?
You can argue a moral standpoint based on the wholly abritrary legal situation; but that's a moot point at best. Like most moral debates it comes down to opinions. There's no hard facts that determine whether a moral standpoint is "right".
Personally I wouldn't use cannabis before climbing as it would negatively affect concentration and cardiovascular function. I would use pasta though and gain the performance-enhancing benefits of increased glycogen stores. I would use beta-alanine...a perfectly safe and legal sports supplement that ...buffers lactic acid. I would use creatine - a perfectly safe sports supplement that enables slightly longer bursts of energy in short, power filled problems. I would use whey protein for recovery. I would use coffe to enhance my concentration. I would use jelly sweets, fruit and nuts for instant top up of key macro nutrients whilst climbing.
Presumably..since those are all legal....the very well evidenced performance enhancing benfeits of them all would be absolutely fine. Bearing in mind there is a HUGE amount of evidence showing all of those offer performance enahncing benefits vs basically none for cannabis in this context.
SO either your moral standpoint is based on the legality....which seems a poor position but each to their own. OR...your moral standpoint is based purely on the performance enhancing aspect..in which case everything in my list should be banned.