I did a rotation this year mid-July through mid-August and had no problems. It was actually probably my best sub-I of the three that I did, and it is probably going to be No. 1 on my list. The interns may be new, but you interact more with PGY2 and higher ortho residents, so they know the ropes by then. At least where I was they seemed to be quite confident and everything went smoothly.
As for getting lost in the shuffle, I think that it was just the opposite. Since I was there so early, I was their first sub-I and I was the only student there for 2 or 3 weeks before others started to come, so they really got to know me and I had my chance to shine and make a good impression.
I don't know if mine was a unique experience, but I would not personally discourage a July sub-I.
:smokin:

On the contrary, I think June/July is a great time to do a sub-internship. Even if the new interns and residents are clueless, it is a great opportunity for you to shine (but not at the expense of your team, of course). I'd go for it.

just to chime in, i matched at the place i did my july away rotation.