Parents.... can't live with them, can't live without them... 
The ongoing rule in my family is that if you are traveling far or live a ways off... you have to call and check in once you arrive at your destination .... as well as call before you leave when coming back from a trip etc... The rule, which shouldn't be a surprise, is one my Mother made... being a natural born worry wart and all..
Well... they had a family funeral to go to that was going to be over a 4 hour trip one way... Since they are in their mid-eighties now... I added in about an hour and a half for supper some place and at least four to six "pit stops" on the way of about fifteen minutes each... so that'd be around seven hours at my worst time calculations... My Uncle had tried to call them about that time to see if there were any traffic issues he would see on the way up when he left... and was unable to reach them. Didn't think much of that, it's mostly a rural route so cell phone reception is likely sketchy at best in some places. When it had been over eight hours... I started calling them myself and again no answer. Their destination isn't a small or tiny town... so they should have cell service. Next... I called the hotel they were going to stay at... they had checked in... so that was a relief... but no answer in their room. My Dad did finally call about fifteen minutes ago.... so all is well. I'm still not certain why it took them an hour longer than it should have... but I'll guess I'll hear about it after they return...
There is of course an upside for me.... payback's for all of the times I was chewed out for not checking in will be fun