Cisco UBR interface with PHP

I have an idea that I wanted to throw out there.  I have a cable ISP
plant that I am trying to help with a project.  They are using Cisco
7114 UBRs to connect their cable modems with their Internet backbone -
this device assigns it a dhcp address and associates it with the modems
MAC address.  It does a lot more than that but that is all I am
concerned with.  I want to see if I can write a script that will
constantly execute the command "show ip arp" which will return the
current routing table with the MAC and IP address (dhcp).  I can foresee
two problems so far, one is that you have to have enable mode access to
run this function and two, I would fear creating a security loophole by
running an enabled function all of the time.  Can I get your thoughts on
this?
thanks,
Doug