No one is going to ask, before the first day on the job, for that kind of alteration to the standard employment contract. They're very likely to lose the offer. Talking about side projects before the first week of work is not a good career move, especially if you're young (22-24) and have no leverage at all.
Add to this that the side project problem isn't relevant for many people, and people can't predict 5-10 years out whether it will be relevant to them. How many 22-year-olds expect to write a $20,000/month iPhone app, some time in the future, and aren't already trying to do it? Also, if you do a side project on your own equipment and time, most of the time you can hide the fact that much of the work occurred while under a surrender-all; if nothing else, just rewrite the code outright after you leave, since the code will be better and take much less time to write on a second write. This means, from a practical standpoint, that most people don't worry about this situation until/unless they end up in the 0.1% it actually affects and it's too late. This law is only relevant to extreme edge cases; for the rest, it merely makes a statement about the meaning of employment, and in the New York case, it makes a disgusting one.
You can definitely get away with this if you steadfastedly request a change to the contract that says that work done outside of the office is your own. There's a war for talent going on... developers have plenty of leverage.
You do have to push hard though, its extra legal work for them and so they'll deter you mainly for that reason.
This presumes you're desperate for work, those that get stuff done have no problem, they approach the business forthrightly and tell them this is what I'm working on, and I want it to be mine. If a business has an objection to a person owning the rights to their work, then you can tell your signing up for indentured servitude rather than employment. It's not a place you want to work for anyway.
I used to have this attitude as well that I couldn't ask for stuff and no one would agree, I gave it up, started approaching things earnestly and honestly and it's amazing the things people will do if you ask them in a respectful and polite manner.
It depends who you are. If you're an established software engineer with a name, sure. If you're a 22-year-old out of college, no chance. Most of us are between those extremes, of course, and generally realize at some point that we've moved into the with-leverage crowd. But nobody starts there.
I actually think it's best, as a general principle, not to work on side projects while employed. If the side project really is a side project (i.e. it's unrelated to your work and therefore something you justly own) you'll do a much better job of it if you work on it full-time. The side project and the day job usually both suffer if you try to serve two masters. But there are cases to which this principle doesn't apply (i.e. an iPhone app that doesn't take much time to build but becomes very popular) and it's for those that we need (in NY) better laws.
Add to this that the side project problem isn't relevant for many people, and people can't predict 5-10 years out whether it will be relevant to them. How many 22-year-olds expect to write a $20,000/month iPhone app, some time in the future, and aren't already trying to do it? Also, if you do a side project on your own equipment and time, most of the time you can hide the fact that much of the work occurred while under a surrender-all; if nothing else, just rewrite the code outright after you leave, since the code will be better and take much less time to write on a second write. This means, from a practical standpoint, that most people don't worry about this situation until/unless they end up in the 0.1% it actually affects and it's too late. This law is only relevant to extreme edge cases; for the rest, it merely makes a statement about the meaning of employment, and in the New York case, it makes a disgusting one.