The best bet is to always practice "plausible deniability." QUOTE]
" Plausable Deniablility " leads most usually to reasonable doubt ; whcih leads to " Probable cause " ,which leads to a warrant for L / E ( Law Enforement ) a living hell. Which goes to an extended and sometimes..exhaustive investigation.
Body language, your speech , how you word your sentences, manner in which you talk. You play dumb..and you might..." Might " find yourself explaing your actions to a prosecutor.
If you have nothing to hide , do not suspect someone was on YOUR computer without you being present , or you were absent..then my advice is to cooperate.
I will not go into detail here..But there is ways of proving when, and who was on a computer. Now, that secion of the investiagion is not always flawless ; and sometimes it is hard to prove..BUT it can be proven , even if you were not there.
Terrorist files , bombing info , how to make homemade beer and wine without the ATF finding out , Jihad websites....Your computer and you were not there..can be proven by a competenat and knowledgable investigator.
You walk in with a Lawyer..........Your call.
FF - Medic !!!