Interesting. My family shares an I-Pass because we go to the Chicago area so often (though usually in different vehicles). Because of the way our account was setup online, there is no bill and no account of toll frequency or location - though I think that there is a way that you can request said service. Every time the I-Pass runs low (around $5.00), the credit card that it is linked to is automatically charged $40.00.
Unless there is an unusual frequency of charges, I guess there is no need to know when or where the charges were incurred. Just remember to try to keep the transmitter in the metallic bag when you aren't using it for extended periods of time. There are other similar frequencies that can set off the transmitter, motion-activated doors at grocery stores are among the biggest offenders (just like with personal radar alerters...not like I would know or anything
)