Do you think its fair to complain about a singer Lip Syncing at a concert when..  

the concert has a lot of dancing involved? i mean seriously how do you expect these people to dance for hours straight and sing at the same time and them not be out of breath? i mean if it was a type of music that has no dancing and the singer or band is just up on stage then yeah i expect them to sing but like people are complaining big time that britney spears (for example) has been Lip Syncing at her concert but every clip i see she is dancing and flipping and all kinds of crazy stuff.. how could she do all that AND sing for the FULL concert??

if she was just standing there then ok.. but jeeze.. or maybe im just sympathetic and understanding due to the fact i used to be a dancer and sing (NOT at the same time) and have asthma so i couldnt even imagine doing it all at the same time lol..

what do you expect at those kind of shows? singing and dancing for hours? or will you be ok if they Lip Sync a little here and there (or more) because the dancing makes up for it?