We've long asked Funai to produce a version of the recorder with at least two sets of IR remote codes so we'd be able to operate two in the same room.
I have a Magnavox DVD/VHS recorder that also reacts to the 515's remote, and I have to keep them apart from each other.
I don't believe anyone's found a way to alter the machine so's to not respond to the remote, but you could turn one machine off and carefully turn the other on.
Some have also simply gotten a piece of cardboard to block the IR receiver "eye" on one machine while they're using the other one.
That might be the better way, because I just tried mine and with the 515 turned off, it reacted to a pressing of the play
button on the remote, turning on.
I do recall people trying some behaviour tests, maybe something like "Will it turn on if it has a DVD in the tray, but was left set on HDD before being turned off?" Odd little "Try this, try that" sorts of things.
Don't believe much came of it, tho'.
If there's something I'm forgetting (not unheard of), hopefully someone else will chime in.
Of course, you COULD sell the Magnavox Blu-ray player and get one by another manufacturer...