Annoyance on the way out was the discovery that the parking lot (one of those recommended by the con website--391 Congress St), which was listed as having a $9 daily rate with no others mentioned, actually as a $24 overnight rate -- not worth not parking in the hotel.
There were two issues. First, the lot seems to deliberately false advertise, only listing their overnight rate on their exit.
Second, the Directions page on the Boskone website seems to have a lot of misleading info re parking lots -- frex, 390 Congress was being bulldozed during the con. Oddly, the page linked to by the hotel page re satellite lots (on bostonadvantage.com) has what looks like much more accurate and complete info, but it bears pretty much no resemblance to that on the Directions page, nor is there a link in that direction.