Sometimes the "highest standard" is subjective, more regulation doesn't mean better regulation. Regulation, as expressed through licensing, also happens as a means to protect industry incumbents. Should the current most stringent taxi licensing be extended across multiple countries? What about cosmetology licenses[1]? It's a non-trivial issue to dissect what laws are worth keeping and what laws aren't, as there are people affected positively or negatively whichever way you go. It's a complex issue.

1: http://www.npr.org/sections/money/2012/06/22/155596305/episo...