That response is quite cursory and a little too generalized. The legal restrictions in this realm are far too stringent to be throwing around terms like “any grassroots effort”.
And NO, foreigners SHOULD NOT DONATE. Not even to the Revolution SuperPAC. It says it in plain English right on the RevolutionPAC website: “Contributions from foreign nationals are prohibited.” I believe US residents with a Green Card are considered citizens for these purposes and may therefore even donate directly to a political candidate’s campaign, but otherwise, NO.
In this post I reproduced a back and forth from the early days of the RevPAC website (which has since been taken down after the website overhaul to make it more professional). You can see there that it was said foreignors cannot donate to the PAC and are instead encouraged to patronize RonPaulSwag.com.
There are also plenty of other ways to help the cause other than money. See tinyurl.com/SupportRonPaul for details.