I think the implications are more "irritating" than "disturbing". OP shouldn't have mentioned SR. I wouldn't be surprised if the guys at Intersango rolled their eyes and thought "Damn, why did you mention *that*, now WTF do we do". They're playing ball in two courts at once and OP crossed the line.
edit: I think OP should change the title of this thread (if possible). Calling something a scam just because it steps on your toes is an overreaction, and, in this case, has portrayed OP in a much worse light that he was trying for with intersango.
The chances that something illegal will happen might be slightly higher when withdrawing to a SR address rather than to some other address. Then again, I didn't have my credit card issuer freeze my card because I used it to get cash from an ATM, even though cash also creates a higher chance of something illegal will happen, when compared to using the card to pay in a store.
I think it is no surprise that people get upset and talk about "scam" since it seems to become common practise among exchange operators to let all deposits go through and to only disclose the fact that an account was frozen when someone tries to withdraw money. This policy creates money for the exchanges by withholding important information from customers. Something like this is commonly called "scam".
I'm interested in seeing if experiences like this will also come up on non-newbie forums...