I had previously asked Full Tilt the question on other players using the same IP. It is ok and their reply is below
"Thank you for contacting the Full Tilt Poker Support Promotions Team; my
name is Kiwi and I'll be happy to assist you.
For your reference, players who sign up through an affiliate are
ineligible to be referred through our Refer-A-Friend program.
As for your second inquiry, players are allowed to use the same
computer; however, please make sure that you keep your account secure
and separate from one another. Additionally, we recommend that players
use different payment processors as another security measure.
On a final note, all rakeback and affiliate related inquiries can be
sent directly to our Affiliates Team at:
affiliates@fulltiltpoker.com .
On behalf of Full Tilt Poker, I wish you the best of luck at the tables.
Should you have any questions or concerns, please do not hesitate to
contact us.
I hope you have a great day!
Regards,
Kiwi
Full Tilt Poker Support"