[playersare]

you can play multiple machines with the same account, Harrah's will just assume you are playing them both yourself (especially if the machines are next to each other).

generally speaking, it won't be a problem if your girlfriend plays somewhere else on the same account for recreational stakes. however, Harrah's would reserve the right to confiscate points or outright ban accounts should they deem any kind of third-party action to be somehow abusive to the system (particularly comps and cashback-wise). the grey area is them not knowing whether said third party is indeed your "girlfriend just playing with my own money", or some other situation which is not necessarily beneficial to the casino.

the "play on same account or separate accounts" debate is as old as the invention of the slot card itself. what's changed in the last few years is the revision of some slot club T&C's aiming to steer every person towards getting their own account. especially if you can double up on a new signup offer (free slot play, loss rebate, buffets etc) then it might be worth it anyway.

but to answer your basic question, no, the same account card in two separate machines does not automatically trigger any red flags.