The video [1] has a recording of a message left on the answering machine of someone who sent a tea bag through the mail to their Congressman. The voice says:
"...envelope from you with a teabag in it. Before we bring it to the police for examination, we thought you'd like to give us an explanation why you sent it to us."
That's followed by a phone number belonging to Rep. John Adler of New Jersey. Per this, the unnamed constituent called and:
"I told her no malice intended and asked if it was illegal to mail a teabag. I told her it was a in protest in response to the votes of the Congressman. I also told her I thought maybe they would enjoy a good cup of tea this afternoon. She was not amused but acted dumb as to why I sent it. She also said a RECORD of this would be made."
Note that this hasn't been confirmed, and there's the slight possibility that it could be a hoax. And, whoever sent it might not have given any indication why they were sending it, and the person who got the letter may have had no clue that certain persons were telling others to send teabags through the mail (!).
There's probably no law against sending teabags through the mail - especially as a form of political protest - and people shouldn't be afraid of or be warned off of doing such things.
That said, sending tea bags is an incredibly stupid thing to do. It's just a stunt. The "tea parties" are just a stunt. Asking politicians stupid questions about hypocrisy is just a stunt.
There are enough stupid stunts on all the reality shows on TV and all the political food fight shows on cable TV. What we need is for politicians to be asked tough questions about their policies to their face on video. That's 100% defensible and if people get in the habit of doing that it will have a huge impact on our entire political system.