Someone With Mass wrote...
1. Do you know how fast a ship like the Normandy can travel? Thousands of kilometers an hour.
Do you know how fast a particle beam or lasers travel?
If there's a giant wall on the other side, then the Collectors would run a even greater risk of ramming that thing.
No, because they would know about it. And also, becaue it can be moved by them. Even watched Stargate? Know what the Iris is?
To put it simple -a remote controlled lid.
2. Okay, let me tell you something. All that relay is made for is to receive data about your ship's mass so it can calculate the amount of power needed to perform the jump. The jump itself is done by injecting dark energy into the drive core, allowing for instant transport.
I'd guess that all the IFF is doing is giving the relay more precise data about the Normandy's mass.
The relays themselves are barely studied and even less understood. You dont' know exactly what tehy do or what the IFF does.
The ships give the relays precise data - it's the IFF that supposedly triggers more advanced transit protocols.
Who's to say it also doesn't do more? Like shoot you into a black hole if you're not a reaper? Explode you mid-transit?
3. Approaching a secondary relay from the exact same coordinates every single time is not only unecessarily complicated, it's also time consuming. The Collectors could be in need of jumping away from approaching curious eyes or if their ship is badly damaged so they can't make it to those exact coordinates. Then they'd be screwed.
So it's a uncomfortable solution IF they are damaged and IF they want to get away from prying eyes?
A lot of IF's there...
and it's not very hard to approch the relay from the same coordinates.
You're grasping at the far ends of paper straws man....
4. After the Collector ship mission, they know that the Collectors are repruposed Protheans, and the Protheans were wiped out roughly fifty thousand years ago. One can assume that the Collectors' creation came not long after that.
That's still 50 000 years of time to build defenses and ships....that's 200 times more than humans were space-faring, adn they built 200+ ships in that time.
Again, only a fool would believe they only have 1 ship.
Oh, no, we can't take any risks. I guess this mission is doomed right from the start, since you don't know every single thing about the people you're recruiting either and it could be a risk having them aboard too.

I won't even dignify that with an answer.
I am fully aware of what's contradicting my opinion. If it's a good one, I'll give credits where cedits is due.
If it's something laughably bad like your theory about static defenses INSIDE A DEBRIS FIELD, then I'll point and laugh.
Laugh away joker. Meanwhile I'll shake my head in pitty of you.