There aren't any noticeable safety differences, which you are again claiming. UK Latex manufacturers claim their weapons are not thrustsafe due to the 2-3 biggest systems in the country specifically having rules whic ban thrusing anyway. That's not the case in smaller systems, some of which which do allow it.If you've been hurt by gaffer tape, then you haven't been hit with a properly made boffer. Most places I know of require cloth tape or cloth covers. Since professional latex manufacuters are unanimous in claiming that their weapons are not thrust-safe, I think we can dismiss the claim of thrust safe latex swords. Thrust safe boffers, however, are extremely common.
As far as cost goes, I seldom spend more than $3 on a boffer of any stripe, and that's assuming I buy everything retail. If I buy wholesale, I can drive my price down substantially. For the cheapest weapons, I can drive the price down to under a buck apiece, and I can crank it out in about ten minutes. So, parts costs are lower, labor time (and thus costs) are lower, and safety is higher.
And once again, we have the lawsuit issue, which no one has responded to yet. Given the noticeable safety differences, should a US larp chance a lawsuit because someone might thrust with a latex sword?
As a first aider in 1-3 events a month for the last 4-5 years I have never seen an injury from a latex weapon - heard of a few, and have seen friction burns fom gaffa tape's on the few occasions they're used any more. Most injuries come from player-on-player, player-on-ground and player-on-wall collisions. This includes a system with full grappling and stabbing allowed, at the same control level of normal European LRP fighting.
And since the Seattle Knghts can apparently fight, staged or not, witout a lawsuit issue with vast safety differences, why shouldn't a LARP, which doesn't?