I hate it when that happens... and they didn't even try to make it look like it was returned unsealed. It looks like half the toy is missing, and the bubble is half empty.
At least if they had repacked it in robot mode, it would be like the occasional Transformers toy that has a different coloured toy to the packaging artwork (like the RID Gold Grimlock & Night Ops Bumblebee).
The staff at stores taking returns really need to do a better job, otherwise it just encourages people to keep defrauding the system.
(those people doing this should be charged with theft or fraud and banned from the store for life)