T-Mobile international texts - free for recipients too?

So I'm about to take a short trip from the US to the UK and I'm looking to take advantage of T-Mobile's free international data and texts.

But for SMS in particular, if I were to send texts to my friends in the US (and they sent texts to me), would they get charged? Let's assume they're not on T-Mobile.

I'm already on the Simple Choice plan and should be good to go. When I spoke with T-Mob and they said that the recipient will be charged, even though I won't be. Anyone got first hand experience with T-Mobile's international texts?

It's not a big deal if they would get charged - I would just use IM through the free data instead, but it's nice to be sure!