How do opponents respond to the Grace Gambit? You might be familiar with Pascal's Wager, also known as Pascal's Gambit. It states that one is best off believing in Christianity, because, if it is true, you'll be saved and go to heaven, and if it is not true, it has still led you a decent life of moral behavior.
As Pascal said, &quot;If you win, you win everything, if you lose, you lose nothing&quot; - i.e, if you're right, you get eternal life, if you're wrong, you only sustain (if any) temporary injuries.
I personally disagree with this wager, but I thought of a related gambit that addresses those that believe in a pseudo-works salvation. It is as follows:

If you are saved by grace, you should want to serve God as heartily
and fully as possible, loving him and your neighbor and doing good
works. If we assume that, if salvation is not by grace, that it is by
works, than you are best off believing in grace in the first place, as
it will fuel you to do good works, and if it turns out to be wrong,
you'll still most probably get into heaven given the amount of good
you've done.

This goes for any degree of human participation, be it a light view of faith/works salvation or a full-fledged Pelagian view of salvation by works.
My question is, how would those that this gambit addresses respond to it? Catholics, Arminians (sort of), Pelagians, any who hold to any degree of human participation of works to salvation, how would you respond to this logic, both biblically and logically?
In sum, why not believe in salvation by grace? It'll fuel you to do good works, and if you're right, you'll be saved. If you're wrong, and salvation is by works, no sweat! You've already done all those good works as a result of grace anyways, so you'll be saved that way too.
This isn't truly an "answer" to the question so to speak, so please excuse my butting in here.  I think it may be helpful, however, for future readers, to do a small deconstruction of this argument from the perspective of a sola fide belief system.  I'm still interested in the other perspectives as well. 

While logically, the gambit seems to make sense, it makes unclear the entire object of the faith in a very relativistic way.  At it's core, the different soteriologies that exist all point, eventually, to a difference in who God is.  The soteriology of salvation by faith alone apart from works implicitly assumes that there is a loving God who has provided a way for us to be near him, and has provided it in such a way so that:


We are freed from having to do works for salvation. 
God is declared righteous and the only one worthy of praise. 


To have a "fall-back" position is to either be unclear or deny the character of God has he has revealed it through Scripture.  In other words, living by the gambit is inherently a lack of faith in the saving power of God via Christ's sacrifice.  It's the kind of relativist "soft belief" that is so pervasive today (for which we have Pascal, among others, to thank).  

It's the Christianized version of the relativistic worldview, which will claim to believe something, but doesn't believe either it's truth or it's power enough to stand it up in contrast to conflicting beliefs.  In other words, it's prideful unbelief masked in believing terms for no true reason other than to allow the one holding the gambit a false sense of security that they've somehow "out-logicked" God, and thus, he can hold God's hand to the fire saying he must save us because of our amazing prowess with finding loopholes.  

In other words, it's another sign of depravity. 

And I say this with great humility, realizing as I write this that I, sadly, am too often subject to this form of unbelief.