This topic can get very heated very quickly with each defending their side strongly.
Hopefully, you are not a troll and just new to the Dis with a valid, yet hot, question. If so, welcome!
I have a similar situation. My DD will be 3 for 19 days when we go this Halloween.
I look at it this way, we've gone 3 times now to WDW with her being free and now I've chosen to go AFTER she turns 3 to enjoy the Halloween festivities so I already made the choice of whether or not to buy her a ticket by choosing to go AFTER she's 3. I have already bought her tickets to the parks,
MNSSHP, the LUAU, and also the Universal Studios parks. As far as I'm concerned, it's stealing. Athough it's a tempting, easy way to steal, it's stealing. WDW has to set limits at some point and I don't think it's up to us to change it on them.
I couldn't do it even if I wanted to. My husband would kill me, both my DD's would rat me out once we're at WDW, and I really wouldn't want to set a bad example for my DD's anyway.
To each his own, though. This is IMHO, of course.