First of all, there is the technical hassle and expense.
The cost would be minimal. Especially when compared to what the Bush admin spent to on mailing every tax payer a letter telling them they would get another envelope containing X dollars from the Bush tax cut.
My biggest reservation comes from my experience as a Memphian. Democrats will do anything possible to coerce voters and defraud the electoral process. Around here, they put people on buses (usually operated by the Ford machine) to go to the polls.
Ok, what the heck is wrong with helping people get to the polls?!?! Both sides work this angle and it is part of the reason why the elderly have such a high voter turnout.
Often times, Democrat poll workers will overlook the law and allow the bus drivers to come in and 'assist' the voters to make sure they vote straight Democrat.
Then your problem is not having a Republican poll worker who is paying attention. Certainly such activity is disgusting and dishonest. Unfortunately BOTH parties play that game. The paper receipt is an attempt to end such games.
No one is going to threaten a voter with leaving them at the poll if they don't vote the right way for one simple reason. BECAUSE THEN YOUR PARTY LOSES THAT VOTER FOREVER! Coercion comes in the form of honey not thumb tacks!
Voter receipts are nothing but an additional technical complication and a trojan horse for voter coercion.
BS. Lack of receipts is an attempt by the GOP to cover up convenient "technical glitches" that go in their favor.
I find it a little too convenient that EVERY single glitch with the new voting machines went in favor of the Republicans. Every single one. From the extra 1,200 votes that the one OH machine added to Bush to the excessive machine failures in Democratic-heavy precincts. The code needs to be open-source.