Do you think this could cause problems with people "auto-saving" data only to wish it destroyed at a later time?
It needs to be obvious to the users that IPFS does lend itself to content not being able to be deleted once uploaded and in that case a user should never upload anything that that they wish to not have accessed via IPFS forever.
I'll update the site to make sure people know that this is the case.
I think it would be very helpful indeed to do so. It's still not going to cure the issue because there will be plenty of people that think "I want to save this forever" only to realize down the road that they were not doing the right thing. But, the disclaimer/warning should, at the very least, be a signal for them to think hard before storing it.