True, but it would be much simpler to hack the Twitter native applications to do the dirty work for you, depending on your purposes.
That, or just use the oauth_secret from the official Twitter applications; those were cracked ages ago, and even if they changed them (thereby breaking all their old applications), they're super-easy to crack again.
Hardening the webpage would still decimate the amount of people with the skill/motivation to pry out tweets. HTML scraping is much more accessible than poking around native, source-less apps. (And if it was still a problem, the same tactics as above would work equally well in native apps.)
That, or just use the oauth_secret from the official Twitter applications; those were cracked ages ago, and even if they changed them (thereby breaking all their old applications), they're super-easy to crack again.