Many of the top cuemakers do not require a deposit unless it is a very unusual or personalized cue. That is because they know they can sell their cues immediately if the original buyers back out.
Some customers still want to give them deposits as they believe it will speed up the process, or, that it gives them the right to bug the crap out of the cuemaker.
I have dealt and talked with several cuemakers who vary on the requirement of a deposit.
Some have required a 50% deposit and the balance just prior to completion.
Some a nominal amount.
Some have required no deposit.
Some refuse to accept any deposit.
The cuemakers requiring 50% down have done so because the design is custom and possibly not to the liking of the wider market and the cuemakers refusing to accept any deposit have basically explained that their cues are very traditional and therefore have a broad appeal.