Hi there,

This is, of course, a hypothetical question.
So, what if one were to stay in Spain illegally for over a year, and then try to leave to go home to the united states? When this person went to the airport, would there be the possibility that someone at customs would notice that he or she had been in the country for over a year and detain/fine him or her?  Any advice on this would help, hypothetically, of course. 
Thanks!

you could get a on the spot fine , added two your passport and many have problem traveling again to any where , hypothetical .

i would do it , as will in time it come back and bite you in the Ass

Sorry, clarification question, what exactly will bite me in the ass, trying to go home or staying in Spain?

Overstayed and got caught. Penalties varied. The worst cases involved heavy fines (1100 euros) and a large stamp in the passport, the kind of stamp you don’t want if you intended to carry on travelling. You could get detained for questioning . SIS II data-base is now accessible at any police station across Schengen-Zones . airports now electronic swipe-passport with out you knowing ....

there lot thinks but for your travel again in time it could stop you from coming two EU , USA and so on again ...