I wish that were true. The RINOs corrupt the newly elected officials if they can. Look at Renee Elmers, supposed Tea Party adherent, turns into full Open Borders RINO, complete with the insults.
Marco Rubio knocks out RINO, now Democrat Charlie Crist with Tea Party support. He dumps the Tea Party with insults as soon as he enters office by not joining the Tea Party caucus. Then he hunkers down with the RINOs before coming out completely Open Borders as not only a supporter of Comprehensive Immigration Reform, but as a full member of the Gand of Eight. That's not working out for him so well, so he's desperately back paddling out of the Open Borders mess.
Infiltrators are just part of it, which is why the Tea Partyers need to carefully screen potential candidates. And if they do go bad, to cull them the next time around.