I sent them a request similar to #1, but my concern was more about the time to transfer bitcoins.  My thought was like this:

1.  I initiate a bitcoin transfer to TradeHill, with an intent to sell them.

2.  I already have money at TradeHill, but I'm out of bitcoins.

3.  They see my transfer request immediately, credit the bitcoins to my account, and reserve some cash in my account equal to the number of bitcoins I transferred times the current market rate, plus some safety margin.

4.  I can sell the bitcoins immediately, and the money reserved in my account becomes "unreserved" after the necessary 6 confirmations.

This would effectively let you transfer bitcoins instantly, assuming you had some $$ in your account to cover them.  The problem now is that I'll see a good sell opportunity, but by the time my bitcoins get there, the opportunity is gone. 

As others have said, adding the user agent string should do the trick.

Also, posted an answer on your SO question

As someone who actually has a trading bot, I obviously wouldn't want to see any kind of extra charge for API calls.  MtGox already probably makes more money in commissions off me than I make off them

Then again, I don't see what this particular bot is trying to accomplish other than flood the market with junk orders that it never intends to execute.  My only guess would be that they are trying to confuse other traders or bots?  I can't see how it could make money doing what it is doing right now, but then again, maybe I'm missing something.

As someone else mentioned, seems like a small charge for excessive order cancellations would be the best way to stop these kinds of bots, if indeed they actually should be stopped (which I'm not entirely convinced of either).

I'm sure they'll figure it out, and it doesn't really bother me that much, but I just wish there was better communication if they know that deposits/withdrawls are going to be delayed.

Same thing here.  Been waiting 3 days, and no response yet from support to my e-mails.

This must be affecting their paxum trasfers as well.  I've been waiting 3 days for a transfer from TradeHill to Paxum.  Emailed TradeHill twice about it, but still haven't gotten any response.

I'm a developer - working on trading bots for the various exchanges.  These days I mostly do C# and ASP.NET MVC development, but also have lots of experience with Java, C, C++, PHP and Objective-C

Were you ever able to get this resolved?  I just did a deposit myself (20BTC) and it went through fine, although it did take a bit longer than I expected (over 2 hours).

Agreed, and ExchangeBitcoins.com has dropped them as well.  This is going to make moving money between exchanges much more difficult.  

Tradehill seems to be switching to Paxum though, hopefully others will follow suit.

Possible, but if they don't have the funds available to back all their deposits, then that doesn't exactly bode well either.

Didn't see this posted anywhere else, but has anyone else noticed that ExchangeBitcoins.com is no longer accepting Dwolla?  And not just for deposits, but for withdrawls as well.  I appreciate the solidarity with TradeHill, but withdrawls too?