Till now I have not been heard of this reasoning.

Why is it for to being necessary to trace calls and numbers?

Is it not for impermissible to be giving the phone itself? If many recruits are to be saying they had been given electronic goods (phone, iPad, laptop, xbox) that in itself is being a violation. No need in finding who calling or texting who.

Perhaps it is not being as bad violation as extra contactings but phone by itself is breaking of the rules.

Swami