This is quite possible & common scenario that PXEClient/BOOTP client and normal Windows Client exists in the same network and share a single scope of IPaddress. Normally, PXEClient are used only for very limited purpose & short period. Hence limiting the lease time for PXEClient/BOOTP is good practice. Windows 2003 & LongHorn support this feature for feeding different lease time for BOOTP and Normal clients.
[This posting is provided "AS IS" with no warranties, and confers no rights.]