HTML Forms that have email addresses pre filled get broken

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Create a standard HTML form which gets pre-filled by a plugin. (i.e.: 
Seamless Donation Paypal plugin, or WooCommerce Checkout page)
2. Seamless donation shortcode [dfx-donate] stores an email address to receive 
paypal donations
3. WooCommerce checkout page when user is logged in pre-fills their own email 
address.

What is the expected output? What do you see instead?
It breaks the HTML form and makes it unusable. The last part of the email 
address gets visible to the user when it shouldn't be.

Example HTML output:
<input type="hidden" name="business" value="<span 
class=&quot;mh-email&quot;>ema<a href=" http:="" www.google.com="" recaptcha="" 
mailhide="" 
d?k="01cgXVNqirMlFnamCG67t_Uw==&amp;c=5uo2kYC4ui08PIH8-HRUwMYuWY8YuWypPGbETNyop-
Y='" 
onclick="window.open('http://www.google.com/recaptcha/mailhide/d?k=01cgXVNqirMlF
namCG67t_Uw==&amp;c=5uo2kYC4ui08PIH8-HRUwMYuWY8YuWypPGbETNyop-Y=', '', 
'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,h
eight=300'); return false;" title="Reveal this e-mail address">
...@domain.com' /&gt;

What version of the product are you using? On what operating system?
WP 4.0, WP-reCaptcha v3.2

Please provide any additional information below.
It would be useful to check whether the email address is inserted in an input 
attribute such as <input value="" />
Or offer some way of deactivating Mailhide for certain shortcodes.

Original issue reported on code.google.com by clem...@renoovodesign.co.uk on 5 Nov 2014 at 4:30