Just an added tip: unplug your phone when you get to the room (and every day when you get back from the pool; the housekeepers plug it back in) so that you don't get phone calls first thing in the morning inviting you to "breakfast." Aaarrghghgh...learned that one the hard way!
We didn't have any problem last year. Just told them several times we're not interested, went and changed into our suits in the lobby bathroom (our rooms weren't ready yet) and off to the pool we went. This year we're going on a referral week from some friends, so we'll give it a listen and may be interested but not at anywhere near $40k!
I am a ninja, I wear clothes that blend into the decor, practice the art of misdirection and hold my breath as I pass within inches of them with them completely unawares. Nah, we usually just tell them we've been many times and aren't interested
There's really no need to give a made up reason for your "no"...but I can see some fun in playing the secretary/mistress game. What you definitely don't want to do is use some objection that opens the door for them. If you say you're hungry or tired or meeting friends or say "maybe tomorrow"...they'll keep coming after you day after day.
I may be wrong but if you do go on the timeshare thing the person your getting the referral from get a credit, $250 rings a bell. And I can personally vouch for the Boss/secretary/business trip ploy ... worked for us!
I think it's over-played, we've never had any problem with smiling and saying "no thank you, we know where everything is and we need to get to our room". This year we were checking in at 7pm, the only ones in the lobby, when he started his spiel I gave my "really, not interested at all" bit and my wife added "I've been traveling all day, I'm grumpy and hungry". He asked if we would see him tomorrow & I replied "nope, I'll be in the pool" as we walked away he asked which one, I laughed & waved. No calls, no bugging, no rudeness, no problem. Maybe we're just lucky?
We've never really had a problem either. Im not "wishy-washy", so when I say no, its polite but firm. We only had one lady get a little mouthy a couple years ago. As we were walking away she said..."SO! You dont wanna save money huh!?!"....to which I replied..."I JUST DID!"