I can tell you when I listed a small contract I had six offers on the same day. To be fair to each buyer they asked each buyer to submit their best offer by the end of the day. Whoever had the best offer, got the contract. This isn't a "tactic", they are simply responding to a change in market. If the demand exceeds the supply, you will have these situations. As another person said, you are not required to get into a bidding war- figure out what you are willing to pay and stick with that. I know for me, I was very happy I didn't have to accept an offer that was $5 off my asking price. And yes, it was with the former
DVC guides- they did a great job for me.